diff --git a/data/json/monsters/bird.json b/data/json/monsters/bird.json
index 9310ad6b4557d..e1bf3d2bbfa90 100644
--- a/data/json/monsters/bird.json
+++ b/data/json/monsters/bird.json
@@ -35,7 +35,18 @@
       "feed": "The %s seems to like you!  It runs around your legs and seems friendly.",
       "pet": "The %s runs around your leg."
     },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "CANPLAY", "SWARMS", "CAN_BE_CULLED" ]
+    "flags": [
+      "SEES",
+      "HEARS",
+      "SMELLS",
+      "ANIMAL",
+      "PATH_AVOID_DANGER_1",
+      "WARM",
+      "CANPLAY",
+      "SWARMS",
+      "CAN_BE_CULLED",
+      "SMALL_HIDER"
+    ]
   },
   {
     "id": "mon_grouse",
@@ -84,7 +95,19 @@
     "reproduction": { "baby_egg": "egg_crow", "baby_count": 4, "baby_timer": 18 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "CANPLAY", "FLIES", "SWARMS", "EATS" ]
+    "flags": [
+      "SEES",
+      "HEARS",
+      "SMELLS",
+      "ANIMAL",
+      "PATH_AVOID_DANGER_1",
+      "WARM",
+      "CANPLAY",
+      "FLIES",
+      "SWARMS",
+      "EATS",
+      "SMALL_HIDER"
+    ]
   },
   {
     "id": "mon_raven",
@@ -118,7 +141,19 @@
     "reproduction": { "baby_egg": "egg_raven", "baby_count": 5, "baby_timer": 18 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "CANPLAY", "FLIES", "SWARMS", "EATS" ]
+    "flags": [
+      "SEES",
+      "HEARS",
+      "SMELLS",
+      "ANIMAL",
+      "PATH_AVOID_DANGER_1",
+      "WARM",
+      "CANPLAY",
+      "FLIES",
+      "SWARMS",
+      "EATS",
+      "SMALL_HIDER"
+    ]
   },
   {
     "id": "mon_bluejay",
@@ -150,7 +185,7 @@
     "reproduction": { "baby_egg": "egg_bluejay", "baby_count": 5, "baby_timer": 18 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "CANPLAY", "FLIES", "SWARMS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "CANPLAY", "FLIES", "SWARMS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_cardinal",
@@ -182,7 +217,7 @@
     "reproduction": { "baby_egg": "egg_cardinal", "baby_count": 3, "baby_timer": 13 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_robin",
@@ -214,7 +249,7 @@
     "reproduction": { "baby_egg": "egg_robin", "baby_count": 3, "baby_timer": 14 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_sparrow",
@@ -246,7 +281,7 @@
     "reproduction": { "baby_egg": "egg_sparrow", "baby_count": 5, "baby_timer": 14 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_duck",
@@ -278,7 +313,7 @@
     "reproduction": { "baby_egg": "egg_duck", "baby_count": 3, "baby_timer": 5 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 5 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_goose_canadian",
@@ -331,7 +366,7 @@
     "reproduction": { "baby_egg": "egg_turkey", "baby_count": 3, "baby_timer": 12 },
     "baby_flags": [ "SPRING", "SUMMER" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SMALL_HIDER" ]
   },
   {
     "id": "mon_pheasant",
@@ -378,7 +413,7 @@
     "harvest": "bird_tiny",
     "upgrades": { "age_grow": 14, "into": "mon_chicken" },
     "//": "Grows up into a standard chicken as a fallback",
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "SWARMS", "CAN_BE_CULLED" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "SWARMS", "CAN_BE_CULLED", "SMALL_HIDER" ]
   },
   {
     "id": "mon_chicken_chick",
@@ -531,7 +566,7 @@
     "special_attacks": [ [ "SHRIEK", 10 ], [ "EAT_CARRION", 40 ], [ "EAT_FOOD", 120 ] ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
     "upgrades": { "half_life": 21, "into_group": "GROUP_CROW_MUTANT" },
-    "flags": [ "SEES", "HEARS", "SMELLS", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "EATS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "EATS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_crow_mutant",
@@ -605,7 +640,19 @@
       "feed": "The %s seems to like you!  It runs around your legs and seems friendly.",
       "pet": "The %s runs around your leg."
     },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS", "CANPLAY", "CAN_BE_CULLED" ]
+    "flags": [
+      "SEES",
+      "HEARS",
+      "SMELLS",
+      "ANIMAL",
+      "PATH_AVOID_DANGER_1",
+      "WARM",
+      "FLIES",
+      "SWARMS",
+      "CANPLAY",
+      "CAN_BE_CULLED",
+      "SMALL_HIDER"
+    ]
   },
   {
     "id": "mon_goose",
@@ -632,7 +679,7 @@
       "feed": "The %s seems to like you!  It runs around your legs and seems friendly.",
       "pet": "The %s runs around your leg."
     },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "CAN_BE_CULLED" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "CAN_BE_CULLED", "SMALL_HIDER" ]
   },
   {
     "id": "mon_goose_golden",
@@ -691,7 +738,7 @@
     "reproduction": { "baby_egg": "egg_hummingbird", "baby_count": 5, "baby_timer": 14 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SMALL_HIDER" ]
   },
   {
     "id": "mon_woodpecker",
@@ -722,7 +769,7 @@
     "reproduction": { "baby_egg": "egg_woodpecker", "baby_count": 5, "baby_timer": 14 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 8 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SMALL_HIDER" ]
   },
   {
     "id": "mon_hummingbird_chick",
@@ -769,7 +816,7 @@
     "reproduction": { "baby_egg": "egg_coot", "baby_count": 3, "baby_timer": 5 },
     "baby_flags": [ "SPRING" ],
     "biosignature": { "biosig_item": "feces_bird", "biosig_timer": 5 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "FLIES", "SWARMS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_cormorant",
diff --git a/data/json/monsters/insect_spider.json b/data/json/monsters/insect_spider.json
index 04768fb6b7014..4d24264c58215 100644
--- a/data/json/monsters/insect_spider.json
+++ b/data/json/monsters/insect_spider.json
@@ -190,7 +190,7 @@
     "harvest": "mutant_meatslug",
     "dissect": "dissect_troglobite_sample_single",
     "upgrades": { "age_grow": 30, "into": "mon_worm" },
-    "extend": { "flags": [ "DIGS", "GOODHEARING" ] },
+    "extend": { "flags": [ "DIGS", "GOODHEARING", "SMALL_HIDER" ] },
     "delete": { "flags": [ "SEES", "SMELLS", "CLIMBS" ] }
   },
   {
@@ -577,7 +577,8 @@
       }
     ],
     "anger_triggers": [ "PLAYER_CLOSE" ],
-    "armor": { "bash": 1, "cut": 2 }
+    "armor": { "bash": 1, "cut": 2 },
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_centipede_mom",
@@ -861,7 +862,7 @@
     "reproduction": { "baby_egg": "egg_firefly", "baby_count": 3, "baby_timer": 15 },
     "baby_flags": [ "SPRING", "SUMMER" ],
     "fear_triggers": [ "HURT", "FIRE" ],
-    "flags": [ "SEES", "HEARS", "FLIES", "STUMBLES" ]
+    "flags": [ "SEES", "HEARS", "FLIES", "STUMBLES", "SMALL_HIDER" ]
   },
   {
     "id": "mon_firefly_larva",
@@ -875,7 +876,8 @@
     "color": "yellow",
     "dissect": "dissect_insect_sample_single",
     "upgrades": { "age_grow": 30, "into": "mon_firefly" },
-    "armor": { "bash": 1, "cut": 2, "stab": 1 }
+    "armor": { "bash": 1, "cut": 2, "stab": 1 },
+    "extend": { "flags": [ "EATS", "SMALL_HIDER" ] }
   },
   {
     "id": "mon_fly_small",
@@ -946,7 +948,7 @@
     "color": "light_green",
     "special_attacks": [ [ "EAT_CARRION", 100 ] ],
     "dissect": "dissect_insect_sample_single",
-    "extend": { "flags": [ "EATS" ] },
+    "extend": { "flags": [ "EATS", "SMALL_HIDER" ] },
     "upgrades": { "age_grow": 30, "into": "mon_fly" }
   },
   {
@@ -1033,7 +1035,7 @@
     "vision_day": 15,
     "upgrades": { "age_grow": 30, "into": "mon_mosquito_giant" },
     "fear_triggers": [ "HURT", "PLAYER_CLOSE", "SOUND" ],
-    "extend": { "flags": [ "SWIMS", "AQUATIC", "WATER_CAMOUFLAGE" ] }
+    "extend": { "flags": [ "SWIMS", "AQUATIC", "WATER_CAMOUFLAGE", "SMALL_HIDER" ] }
   },
   {
     "id": "mon_mosquito_mega",
@@ -1145,7 +1147,7 @@
     "vision_day": 5,
     "vision_night": 5,
     "upgrades": { "age_grow": 30, "into": "mon_spider_cellar_giant" },
-    "extend": { "flags": [ "WEBWALK" ] }
+    "extend": { "flags": [ "WEBWALK", "SMALL_HIDER" ] }
   },
   {
     "id": "mon_spider_cellar_mom",
@@ -1371,7 +1373,8 @@
     "families": [ "prof_intro_biology", "prof_physiology", "prof_wp_basic_bug", "prof_wp_spider" ],
     "vision_day": 5,
     "vision_night": 5,
-    "upgrades": { "age_grow": 30, "into": "mon_spider_jumping_giant" }
+    "upgrades": { "age_grow": 30, "into": "mon_spider_jumping_giant" },
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_spider_jumping_mega",
@@ -1463,7 +1466,7 @@
     "vision_day": 5,
     "vision_night": 5,
     "upgrades": { "age_grow": 30, "into": "mon_spider_trapdoor_giant" },
-    "extend": { "flags": [ "CAN_DIG", "WEBWALK" ] }
+    "extend": { "flags": [ "CAN_DIG", "WEBWALK", "SMALL_HIDER" ] }
   },
   {
     "id": "mon_spider_trapdoor_mega",
@@ -1573,7 +1576,7 @@
     "vision_day": 5,
     "vision_night": 5,
     "upgrades": { "age_grow": 30, "into": "mon_spider_web" },
-    "extend": { "flags": [ "WEBWALK" ] },
+    "extend": { "flags": [ "WEBWALK", "SMALL_HIDER" ] },
     "armor": { "bash": 2, "cut": 6, "bullet": 5 }
   },
   {
@@ -1664,7 +1667,7 @@
     "vision_day": 5,
     "vision_night": 5,
     "upgrades": { "age_grow": 30, "into": "mon_spider_widow_giant" },
-    "extend": { "flags": [ "WEBWALK" ] },
+    "extend": { "flags": [ "WEBWALK", "SMALL_HIDER" ] },
     "armor": { "bash": 2, "cut": 4, "bullet": 3 }
   },
   {
@@ -1740,7 +1743,8 @@
     "families": [ "prof_intro_biology", "prof_physiology", "prof_wp_basic_bug", "prof_wp_spider" ],
     "vision_day": 5,
     "vision_night": 5,
-    "upgrades": { "age_grow": 30, "into": "mon_spider_wolf_giant" }
+    "upgrades": { "age_grow": 30, "into": "mon_spider_wolf_giant" },
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_spider_wolf_mega",
@@ -1852,7 +1856,19 @@
     "upgrades": { "half_life": 30, "into": "mon_wasp" },
     "zombify_into": "mon_meat_cocoon_tiny",
     "fungalize_into": "mon_wasp_small_fungus",
-    "flags": [ "SEES", "SMELLS", "HEARS", "FLIES", "SWARMS", "GROUP_MORALE", "CANPLAY", "PATH_AVOID_FIRE", "HARDTOSHOOT", "EATS" ],
+    "flags": [
+      "SEES",
+      "SMELLS",
+      "HEARS",
+      "FLIES",
+      "SWARMS",
+      "GROUP_MORALE",
+      "CANPLAY",
+      "PATH_AVOID_FIRE",
+      "HARDTOSHOOT",
+      "EATS",
+      "SMALL_HIDER"
+    ],
     "armor": { "bash": 1, "cut": 6, "stab": 4 }
   },
   {
@@ -2026,7 +2042,7 @@
     "melee_damage": [ { "damage_type": "cut", "amount": 1 } ],
     "dodge": 1,
     "upgrades": { "age_grow": 61, "into": "mon_dermatik" },
-    "extend": { "flags": [ "CAN_DIG" ] }
+    "extend": { "flags": [ "CAN_DIG", "SMALL_HIDER" ] }
   },
   {
     "id": "mon_dermatik",
@@ -2621,7 +2637,8 @@
       [ "EAT_CROP", 60 ],
       [ "BROWSE", 60 ],
       [ "GRAZE", 800 ]
-    ]
+    ],
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_aphid_small",
@@ -2677,7 +2694,7 @@
     "reproduction": { "baby_monster": "mon_aphid_small", "baby_count": 1, "baby_timer": 20 },
     "baby_flags": [ "SPRING", "SUMMER" ],
     "biosignature": { "biosig_item": "honeydew", "biosig_timer": 600 },
-    "flags": [ "SEES", "HEARS", "SMELLS", "CLIMBS", "PATH_AVOID_FIRE", "PATH_AVOID_FALL", "SWARMS" ],
+    "flags": [ "SEES", "HEARS", "SMELLS", "CLIMBS", "PATH_AVOID_FIRE", "PATH_AVOID_FALL", "SWARMS", "SMALL_HIDER" ],
     "armor": { "bash": 2, "cut": 5, "bullet": 3 }
   },
   {
@@ -2781,7 +2798,8 @@
       }
     ],
     "anger_triggers": [ "PLAYER_CLOSE" ],
-    "armor": { "bash": 1, "cut": 2, "bullet": 1 }
+    "armor": { "bash": 1, "cut": 2, "bullet": 1 },
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_mantis_mega",
@@ -3008,7 +3026,8 @@
       "reproduction": { "baby_egg": "egg_grasshopper", "baby_count": 3, "baby_timer": 15 },
       "baby_flags": [ "SPRING", "SUMMER", "AUTUMN" ]
     },
-    "upgrades": { "half_life": 35, "into": "mon_grasshopper_giant" }
+    "upgrades": { "half_life": 35, "into": "mon_grasshopper_giant" },
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_grasshopper_giant",
@@ -3079,7 +3098,8 @@
       [ "EAT_CROP", 100 ],
       [ "GRAZE", 133 ],
       [ "BROWSE", 133 ]
-    ]
+    ],
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_stag_beetle_larva",
@@ -3402,7 +3422,7 @@
     "baby_flags": [ "SPRING", "SUMMER", "AUTUMN" ],
     "anger_triggers": [ "PLAYER_WEAK" ],
     "fear_triggers": [ "FIRE", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "SWIMS" ],
+    "flags": [ "SEES", "HEARS", "SMELLS", "SWIMS", "SMALL_HIDER" ],
     "armor": { "bash": 1, "cut": 3, "bullet": 2 }
   },
   {
@@ -3415,7 +3435,7 @@
     "symbol": "s",
     "color": "light_gray",
     "upgrades": { "age_grow": 30, "into": "mon_strider_giant" },
-    "extend": { "flags": [ "SWIMS" ] }
+    "extend": { "flags": [ "SWIMS", "SMALL_HIDER" ] }
   },
   {
     "id": "mon_butterfly",
@@ -3735,7 +3755,8 @@
     "stomach_size": 60,
     "color": "white",
     "harvest": "mutant_shellfish",
-    "upgrades": { "age_grow": 21, "into": "mon_woodlouse" }
+    "upgrades": { "age_grow": 21, "into": "mon_woodlouse" },
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_diving_larva",
@@ -3766,7 +3787,8 @@
     "anger_triggers": [ "PLAYER_CLOSE" ],
     "fear_triggers": [ "HURT" ],
     "flags": [ "AQUATIC", "SEES", "WATER_CAMOUFLAGE" ],
-    "upgrades": { "age_grow": 21, "into": "mon_diving_beetle_small" }
+    "upgrades": { "age_grow": 21, "into": "mon_diving_beetle_small" },
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_diving_beetle_small",
diff --git a/data/json/monsters/mammal.json b/data/json/monsters/mammal.json
index ce0025abb3ca9..88ac7cdfa6690 100644
--- a/data/json/monsters/mammal.json
+++ b/data/json/monsters/mammal.json
@@ -63,7 +63,7 @@
     "vision_night": 20,
     "special_attacks": [ { "type": "bite", "cooldown": 15 } ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "SMELLS", "HEARS", "GOODHEARING", "WARM", "FLIES", "ANIMAL", "PATH_AVOID_DANGER_1" ]
+    "flags": [ "SEES", "SMELLS", "HEARS", "GOODHEARING", "WARM", "FLIES", "ANIMAL", "PATH_AVOID_DANGER_1", "SMALL_HIDER" ]
   },
   {
     "id": "mon_bear_cub",
@@ -195,7 +195,7 @@
     "anger_triggers": [ "PLAYER_WEAK" ],
     "fear_triggers": [ "PLAYER_CLOSE" ],
     "special_attacks": [ [ "EAT_FOOD", 120 ], [ "BROWSE", 120 ] ],
-    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ANIMAL", "STUMBLES", "PATH_AVOID_DANGER_1", "EATS" ]
+    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ANIMAL", "STUMBLES", "PATH_AVOID_DANGER_1", "EATS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_lab_rat",
@@ -246,7 +246,8 @@
       "ANIMAL",
       "PATH_AVOID_DANGER_1",
       "CAN_BE_CULLED",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -282,7 +283,7 @@
     "upgrades": { "age_grow": 38, "into": "mon_boar_wild" },
     "biosignature": { "biosig_item": "feces_manure", "biosig_timer": 7 },
     "special_attacks": [ [ "EAT_FOOD", 40 ], [ "EAT_CARRION", 60 ] ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "KEENNOSE", "EATS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "KEENNOSE", "EATS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_boar_wild",
@@ -363,7 +364,7 @@
     "harvest": "cat_medium_with_skull",
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "dissect": "dissect_feline_sample_single",
-    "flags": [ "SEES", "HEARS", "GOODHEARING", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "HIT_AND_RUN" ]
+    "flags": [ "SEES", "HEARS", "GOODHEARING", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "HIT_AND_RUN", "SMALL_HIDER" ]
   },
   {
     "id": "mon_cat_kitten",
@@ -677,7 +678,7 @@
     "dissect": "dissect_mouse_sample_single",
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "ANIMAL", "PATH_AVOID_DANGER_1" ]
+    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "ANIMAL", "PATH_AVOID_DANGER_1", "SMALL_HIDER" ]
   },
   {
     "id": "mon_cougar",
@@ -1078,7 +1079,7 @@
     "vision_night": 4,
     "harvest": "dog_small_with_skull",
     "upgrades": { "age_grow": 42, "into": "mon_dog" },
-    "extend": { "flags": [ "NO_BREED" ] },
+    "extend": { "flags": [ "NO_BREED", "SMALL_HIDER" ] },
     "delete": { "flags": [ "CORNERED_FIGHTER" ] }
   },
   {
@@ -1167,7 +1168,8 @@
       "SEES",
       "SMELLS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1257,7 +1259,8 @@
       "SEES",
       "SMELLS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1301,7 +1304,8 @@
       "SWARMS",
       "WARM",
       "CORNERED_FIGHTER",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1354,7 +1358,8 @@
       "SMELLS",
       "SWARMS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1444,7 +1449,8 @@
       "SEES",
       "SMELLS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1518,7 +1524,8 @@
       "SMELLS",
       "SWARMS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1561,7 +1568,8 @@
       "SEES",
       "SMELLS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1613,7 +1621,8 @@
       "SEES",
       "SMELLS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1656,7 +1665,8 @@
       "SMELLS",
       "STUMBLES",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1709,7 +1719,8 @@
       "SMELLS",
       "STUMBLES",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1797,7 +1808,8 @@
       "SEES",
       "SMELLS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1893,7 +1905,8 @@
       "SEES",
       "SMELLS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -1988,7 +2001,8 @@
       "SEES",
       "SMELLS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -2080,7 +2094,8 @@
       "SEES",
       "SMELLS",
       "WARM",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -2139,7 +2154,18 @@
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "anger_triggers": [ "FRIEND_ATTACKED", "FRIEND_DIED" ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "HIT_AND_RUN", "KEENNOSE", "CLIMBS" ]
+    "flags": [
+      "SEES",
+      "HEARS",
+      "SMELLS",
+      "ANIMAL",
+      "PATH_AVOID_DANGER_1",
+      "WARM",
+      "HIT_AND_RUN",
+      "KEENNOSE",
+      "CLIMBS",
+      "SMALL_HIDER"
+    ]
   },
   {
     "id": "mon_fox_red",
@@ -2171,7 +2197,7 @@
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "anger_triggers": [ "FRIEND_ATTACKED", "FRIEND_DIED" ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "HIT_AND_RUN", "KEENNOSE" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "HIT_AND_RUN", "KEENNOSE", "SMALL_HIDER" ]
   },
   {
     "id": "mon_groundhog",
@@ -2201,7 +2227,7 @@
     "stomach_size": 30,
     "special_attacks": [ [ "GRAZE", 100 ] ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "GOODHEARING", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "EATS" ]
+    "flags": [ "SEES", "HEARS", "GOODHEARING", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "EATS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_hare",
@@ -2387,7 +2413,18 @@
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "anger_triggers": [ "FRIEND_ATTACKED", "FRIEND_DIED" ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "HIT_AND_RUN", "KEENNOSE", "SWIMS" ]
+    "flags": [
+      "SEES",
+      "HEARS",
+      "SMELLS",
+      "ANIMAL",
+      "PATH_AVOID_DANGER_1",
+      "WARM",
+      "HIT_AND_RUN",
+      "KEENNOSE",
+      "SWIMS",
+      "SMALL_HIDER"
+    ]
   },
   {
     "id": "mon_moose",
@@ -2572,7 +2609,7 @@
     "dissect": "dissect_rat_sample_single",
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ANIMAL", "PATH_AVOID_DANGER_1" ]
+    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ANIMAL", "PATH_AVOID_DANGER_1", "SMALL_HIDER" ]
   },
   {
     "id": "mon_opossum",
@@ -2603,7 +2640,7 @@
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "anger_triggers": [ "FRIEND_ATTACKED", "HURT" ],
     "fear_triggers": [ "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "CLIMBS", "PATH_AVOID_DANGER_1", "WARM", "KEENNOSE", "EATS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "CLIMBS", "PATH_AVOID_DANGER_1", "WARM", "KEENNOSE", "EATS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_otter",
@@ -2630,7 +2667,7 @@
     "harvest": "mammal_small_fur",
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "SWIMS", "WARM", "WATER_CAMOUFLAGE" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "SWIMS", "WARM", "WATER_CAMOUFLAGE", "SMALL_HIDER" ]
   },
   {
     "id": "mon_pig_piglet",
@@ -2675,7 +2712,8 @@
       "WARM",
       "KEENNOSE",
       "CAN_BE_CULLED",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -2765,7 +2803,8 @@
       "WARM",
       "CAN_BE_CULLED",
       "GOODHEARING",
-      "EATS"
+      "EATS",
+      "SMALL_HIDER"
     ]
   },
   {
@@ -2849,7 +2888,7 @@
     "upgrades": { "half_life": 30, "into": "mon_raccoon_mutant" },
     "special_attacks": [ [ "EAT_FOOD", 60 ], [ "BROWSE", 50 ], [ "EAT_CARRION", 60 ] ],
     "anger_triggers": [ "FRIEND_ATTACKED", "HURT" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "CLIMBS", "PATH_AVOID_DANGER_1", "WARM", "KEENNOSE", "EATS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "CLIMBS", "PATH_AVOID_DANGER_1", "WARM", "KEENNOSE", "EATS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_sewer_rat",
@@ -2885,7 +2924,7 @@
     "upgrades": { "half_life": 42, "into_group": "GROUP_RATKIN_EVOLVED" },
     "path_settings": { "max_dist": 10 },
     "anger_triggers": [ "PLAYER_WEAK", "FRIEND_ATTACKED", "FRIEND_DIED" ],
-    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ANIMAL", "PATH_AVOID_DANGER_1", "STUMBLES", "EATS" ]
+    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ANIMAL", "PATH_AVOID_DANGER_1", "STUMBLES", "EATS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_sheep_lamb",
@@ -3044,7 +3083,7 @@
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "special_attacks": [ [ "BROWSE", 120 ] ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "STUMBLES", "WARM", "EATS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "STUMBLES", "WARM", "EATS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_squirrel_red",
@@ -3075,7 +3114,7 @@
     "dissect": "dissect_mouse_sample_single",
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "STUMBLES", "WARM", "EATS" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "STUMBLES", "WARM", "EATS", "SMALL_HIDER" ]
   },
   {
     "id": "mon_weasel",
@@ -3102,7 +3141,7 @@
     "harvest": "mammal_tiny",
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "SWIMS", "WARM" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "SWIMS", "WARM", "SMALL_HIDER" ]
   },
   {
     "id": "mon_wolf",
@@ -3225,7 +3264,8 @@
     "harvest": "mammal_fur",
     "dissect": "dissect_cattle_sample_single",
     "special_attacks": [ [ "EAT_CROP", 60 ], [ "GRAZE", 60 ] ],
-    "upgrades": { "age_grow": 500, "into": "mon_reindeer" }
+    "upgrades": { "age_grow": 500, "into": "mon_reindeer" },
+    "extend": { "flags": [ "SMALL_HIDER" ] }
   },
   {
     "id": "mon_llama_calf",
@@ -3343,7 +3383,18 @@
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "reproduction": { "baby_monster": "mon_ferret_kit", "baby_count": 5, "baby_timer": 100 },
     "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "SWIMS", "WARM", "CANPLAY", "CAN_BE_CULLED" ]
+    "flags": [
+      "SEES",
+      "HEARS",
+      "SMELLS",
+      "ANIMAL",
+      "PATH_AVOID_DANGER_1",
+      "SWIMS",
+      "WARM",
+      "CANPLAY",
+      "CAN_BE_CULLED",
+      "SMALL_HIDER"
+    ]
   },
   {
     "id": "mon_ferret_kit",
diff --git a/data/json/monsters/rodentkin.json b/data/json/monsters/rodentkin.json
index bd2a6845313c7..e816ec818294f 100644
--- a/data/json/monsters/rodentkin.json
+++ b/data/json/monsters/rodentkin.json
@@ -43,7 +43,19 @@
     "stomach_size": 30,
     "fear_triggers": [ "PLAYER_CLOSE", "SOUND" ],
     "special_attacks": [ [ "EAT_FOOD", 120 ] ],
-    "flags": [ "SEES", "SMELLS", "HEARS", "KEENNOSE", "CANPLAY", "WARM", "SWIMS", "ANIMAL", "PATH_AVOID_DANGER_1", "EATS" ]
+    "flags": [
+      "SEES",
+      "SMELLS",
+      "HEARS",
+      "KEENNOSE",
+      "CANPLAY",
+      "WARM",
+      "SWIMS",
+      "ANIMAL",
+      "PATH_AVOID_DANGER_1",
+      "EATS",
+      "SMALL_HIDER"
+    ]
   },
   {
     "id": "mon_big_rat",
@@ -87,7 +99,7 @@
       [ "EAT_CARRION", 120 ]
     ],
     "attack_effs": [ { "id": "rat_bite_fever", "duration": 400, "chance": 10 } ],
-    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ANIMAL", "PATH_AVOID_DANGER_1", "EATS" ],
+    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ANIMAL", "PATH_AVOID_DANGER_1", "EATS", "SMALL_HIDER" ],
     "families": [ "prof_intro_biology", "prof_physiology" ],
     "harvest": "mutant_mammal_small_fur",
     "dissect": "dissect_rat_sample_single"
@@ -109,7 +121,7 @@
     "special_attacks": [ [ "EAT_FOOD", 120 ], [ "EAT_CARRION", 120 ] ],
     "families": [ "prof_intro_biology", "prof_physiology", "prof_electromagnetics" ],
     "upgrades": { "half_life": 42, "into_group": "GROUP_RATKIN_EVOLVED" },
-    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ELECTRIC", "ANIMAL", "PATH_AVOID_DANGER_1", "EATS" ],
+    "flags": [ "SEES", "SMELLS", "HEARS", "WARM", "SWIMS", "ELECTRIC", "ANIMAL", "PATH_AVOID_DANGER_1", "EATS", "SMALL_HIDER" ],
     "emit_fields": [ { "emit_id": "emit_shock_burst_rat", "delay": "5 s" } ]
   },
   {