diff --git a/data/raw/keybindings.json b/data/raw/keybindings.json
index e769effd02ea8..f2b022134a298 100644
--- a/data/raw/keybindings.json
+++ b/data/raw/keybindings.json
@@ -1234,6 +1234,13 @@
     "name": "Teleport to cursor",
     "bindings": [ { "input_method": "keyboard_any", "key": "d" } ]
   },
+  {
+    "type": "keybinding",
+    "id": "MODIFY_HORDE",
+    "category": "OVERMAP",
+    "name": "Modify existing horde or place new one",
+    "bindings": [ { "input_method": "keyboard_any", "key": "p" } ]
+  },
   {
     "type": "keybinding",
     "name": "View missions",
diff --git a/src/debug_menu.h b/src/debug_menu.h
index 24bcfb2c54413..9d8e3bbe6bd94 100644
--- a/src/debug_menu.h
+++ b/src/debug_menu.h
@@ -12,6 +12,7 @@
 
 class Character;
 class Creature;
+struct mongroup;
 struct tripoint;
 
 template <typename E> struct enum_traits;
@@ -121,6 +122,8 @@ void wishitem( Character *you = nullptr );
 void wishitem( Character *you, const tripoint & );
 void wishitem( Character *you, const tripoint_bub_ms & );
 void wishmonster( const std::optional<tripoint> &p );
+void wishmonstergroup( tripoint_abs_omt &loc );
+void wishmonstergroup_mon_selection( mongroup &group );
 void wishmutate( Character *you );
 void wishbionics( Character *you );
 /*
diff --git a/src/mongroup.cpp b/src/mongroup.cpp
index dea2a253025ef..ced65049c4b2f 100644
--- a/src/mongroup.cpp
+++ b/src/mongroup.cpp
@@ -449,6 +449,11 @@ void MonsterGroupManager::FinalizeMonsterGroups()
     }
 }
 
+std::map<mongroup_id, MonsterGroup> &MonsterGroupManager::Get_all_Groups()
+{
+    return MonsterGroupManager::monsterGroupMap;
+}
+
 void MonsterGroupManager::LoadMonsterGroup( const JsonObject &jo )
 {
     float mon_upgrade_factor = get_option<float>( "MONSTER_UPGRADE_FACTOR" );
diff --git a/src/mongroup.h b/src/mongroup.h
index 5855582abb8d2..d99ccb7f4e756 100644
--- a/src/mongroup.h
+++ b/src/mongroup.h
@@ -224,6 +224,9 @@ class MonsterGroupManager
 
         static bool is_animal( const mongroup_id &group );
 
+        // Public getter for private monsterGroupMap, do not use if you don't know what you're doing.
+        static std::map<mongroup_id, MonsterGroup> &Get_all_Groups();
+
     private:
         static std::map<mongroup_id, MonsterGroup> monsterGroupMap;
         using t_string_set = std::set<std::string>;
diff --git a/src/overmap.cpp b/src/overmap.cpp
index 07d72f010e8b4..8a7788a3554b1 100644
--- a/src/overmap.cpp
+++ b/src/overmap.cpp
@@ -7553,6 +7553,23 @@ void overmap::debug_force_add_group( const mongroup &group )
     add_mon_group( group, 1 );
 }
 
+std::vector<std::reference_wrapper<mongroup>> overmap::debug_unsafe_get_groups_at(
+            tripoint_abs_omt &loc )
+{
+    point_abs_om overmap;
+    tripoint_om_omt omt_within_overmap;
+    std::tie( overmap, omt_within_overmap ) = project_remain<coords::om>( loc );
+    tripoint_om_sm om_sm_pos = project_to<coords::sm>( omt_within_overmap );
+
+    std::vector<std::reference_wrapper <mongroup>> groups_at;
+    for( std::pair<const tripoint_om_sm, mongroup> &pair : zg ) {
+        if( pair.first == om_sm_pos ) {
+            groups_at.emplace_back( pair.second );
+        }
+    }
+    return groups_at;
+}
+
 void overmap::add_mon_group( const mongroup &group )
 {
     zg.emplace( group.rel_pos(), group );
diff --git a/src/overmap.h b/src/overmap.h
index d24af49002727..75c669ef910a2 100644
--- a/src/overmap.h
+++ b/src/overmap.h
@@ -540,6 +540,7 @@ class overmap
 
         // DEBUG ONLY!
         void debug_force_add_group( const mongroup &group );
+        std::vector<std::reference_wrapper<mongroup>> debug_unsafe_get_groups_at( tripoint_abs_omt &loc );
     private:
         /**
          * Iterate over the overmap and place the quota of specials.
diff --git a/src/overmap_ui.cpp b/src/overmap_ui.cpp
index 313a015dab552..389c7eb773807 100644
--- a/src/overmap_ui.cpp
+++ b/src/overmap_ui.cpp
@@ -35,6 +35,7 @@
 #include "cuboid_rectangle.h"
 #include "cursesdef.h"
 #include "display.h"
+#include "debug_menu.h"
 #include "game.h"
 #include "game_constants.h"
 #include "game_ui.h"
@@ -1151,6 +1152,7 @@ static void draw_om_sidebar( ui_adaptor &ui,
         print_hint( "PLACE_SPECIAL", c_light_blue );
         print_hint( "SET_SPECIAL_ARGS", c_light_blue );
         print_hint( "LONG_TELEPORT", c_light_blue );
+        print_hint( "MODIFY_HORDE", c_light_blue );
         ++y;
     }
 
@@ -1627,6 +1629,92 @@ static void set_special_args( tripoint_abs_omt &curs )
     *maybe_args = args;
 }
 
+static void modify_horde_func( tripoint_abs_omt &curs )
+{
+    overmap &map_at_cursor = overmap_buffer.get( project_to<coords::om>( curs ).xy() );
+    std::vector<std::reference_wrapper<mongroup>> hordes =
+                map_at_cursor.debug_unsafe_get_groups_at( curs );
+    if( hordes.empty() ) {
+        if( !query_yn( _( "No hordes there.  Would you like to make a new horde?" ) ) ) {
+            return;
+        } else {
+            debug_menu::wishmonstergroup( curs );
+            return;
+        }
+    }
+    uilist horde_list;
+    int entry_num = 0;
+    for( auto &horde_wrapper : hordes ) {
+        mongroup &mg = horde_wrapper.get();
+        // We do some special handling here to provide the information in as simple a way as possible
+        // emulates horde behavior
+        int displayed_monster_num = mg.monsters.empty() ? mg.population : mg.monsters.size();
+        std::string horde_description = string_format( _( "group(type: %s) with %d monsters" ),
+                                        mg.type.c_str(), displayed_monster_num );
+        horde_list.addentry( entry_num, true, -1, horde_description );
+    }
+    horde_list.query();
+    int &selected_group = horde_list.ret;
+    if( selected_group < 0 || static_cast<size_t>( selected_group ) > hordes.size() ) {
+        return;
+    }
+    mongroup &chosen_group = hordes[selected_group];
+
+    uilist smenu;
+    smenu.addentry( 0, true, 'I', _( "Set horde's interest (in %%)" ) );
+    smenu.addentry( 1, true, 'D', _( "Set horde's destination" ) );
+    smenu.addentry( 2, true, 'P', _( "Modify horde's population" ) );
+    smenu.addentry( 3, true, 'M', _( "Add a new monster to the horde" ) );
+    smenu.addentry( 4, true, 'B', _( "Set horde behavior" ) );
+    smenu.addentry( 5, true, 'T', _( "Set horde's boolean values" ) );
+    smenu.addentry( 6, true, 'A', _( "Add another horde to this location" ) );
+    smenu.query();
+    int new_value = 0;
+    tripoint_abs_omt horde_destination = tripoint_abs_omt_zero;
+    switch( smenu.ret ) {
+        case 0:
+            query_int( new_value, _( "Set interest to what value?  Currently %d" ), chosen_group.interest );
+            chosen_group.set_interest( new_value );
+            break;
+        case 1:
+            popup( _( "Select a target destination for the horde." ) );
+            horde_destination = ui::omap::choose_point( true );
+            if( horde_destination == overmap::invalid_tripoint || horde_destination == tripoint_abs_omt_zero ) {
+                break;
+            }
+            chosen_group.target = project_to<coords::sm>( horde_destination ).xy();
+            break;
+        case 2:
+            query_int( new_value, _( "Set population to what value?  Currently %d" ), chosen_group.population );
+            chosen_group.population = new_value;
+            break;
+        case 3:
+            debug_menu::wishmonstergroup_mon_selection( chosen_group );
+            break;
+        case 4:
+            // Screw it we hardcode a popup, if you really want to use this you're welcome to improve it
+            popup( _( "Set behavior to which enum value?  Currently %d.  \nAccepted values:\n0 = none,\n1 = city,\n2=roam,\n3=nemesis" ),
+                   static_cast<int>( chosen_group.behaviour ) );
+            query_int( new_value, "" );
+            chosen_group.behaviour = static_cast<mongroup::horde_behaviour>( new_value );
+            break;
+        case 5:
+            // One day we'll be able to simply convert booleans to strings...
+            chosen_group.horde = query_yn(
+                                     _( "Set group's \"horde\" value to true?  (Select no to set to false)  \nCurrently %s" ),
+                                     chosen_group.horde ? _( "true" ) : _( "false" ) );
+            chosen_group.dying = query_yn(
+                                     _( "Set group's \"dying\" value to true?  (Select no to set to false)  \nCurrently %s" ),
+                                     chosen_group.dying ? _( "true" ) : _( "false" ) );
+            break;
+        case 6:
+            debug_menu::wishmonstergroup( curs );
+            break;
+        default:
+            break;
+    }
+}
+
 static std::vector<tripoint_abs_omt> get_overmap_path_to( const tripoint_abs_omt &dest,
         bool driving )
 {
@@ -1807,6 +1895,7 @@ static tripoint_abs_omt display()
         ictxt.register_action( "PLACE_SPECIAL" );
         ictxt.register_action( "SET_SPECIAL_ARGS" );
         ictxt.register_action( "LONG_TELEPORT" );
+        ictxt.register_action( "MODIFY_HORDE" );
     }
     ictxt.register_action( "QUIT" );
     std::string action;
@@ -2012,6 +2101,9 @@ static tripoint_abs_omt display()
             g->place_player_overmap( curs );
             add_msg( _( "You teleport to submap %s." ), curs.to_string() );
             action = "QUIT";
+        } else if( action == "MODIFY_HORDE" ) {
+            modify_horde_func( curs );
+            action = "QUIT";
         } else if( action == "MISSIONS" ) {
             g->list_missions();
         }
@@ -2279,6 +2371,7 @@ void ui::omap::display()
 {
     g->overmap_data = overmap_ui::overmap_draw_data_t(); //reset data
     g->overmap_data.origin_pos = get_player_character().global_omt_location();
+    g->overmap_data.debug_editor = debug_mode; // always display debug editor if game is in debug mode
     overmap_ui::display();
 }
 
diff --git a/src/wish.cpp b/src/wish.cpp
index a687deb4468c8..0a689826028ca 100644
--- a/src/wish.cpp
+++ b/src/wish.cpp
@@ -29,7 +29,10 @@
 #include "item_factory.h"
 #include "itype.h"
 #include "localized_comparator.h"
+#include "overmap.h"
+#include "overmapbuffer.h"
 #include "map.h"
+#include "mongroup.h"
 #include "monster.h"
 #include "monstergenerator.h"
 #include "mtype.h"
@@ -49,6 +52,8 @@
 
 static const efftype_id effect_pet( "pet" );
 
+static const mongroup_id GROUP_ZOMBIE( "GROUP_ZOMBIE" );
+
 class ui_adaptor;
 
 class wish_mutate_callback: public uilist_callback
@@ -713,26 +718,97 @@ class wish_monster_callback: public uilist_callback
         ~wish_monster_callback() override = default;
 };
 
+static void setup_wishmonster( uilist &pick_a_monster, std::vector<const mtype *> &mtypes )
+{
+    pick_a_monster.desired_bounds = { -1.0, -1.0, 1.0, 1.0 };
+    pick_a_monster.selected = uistate.wishmonster_selected;
+    int i = 0;
+    for( const mtype &montype : MonsterGenerator::generator().get_all_mtypes() ) {
+        pick_a_monster.addentry( i, true, 0, montype.nname() );
+        pick_a_monster.entries[i].extratxt.txt = montype.sym;
+        pick_a_monster.entries[i].extratxt.color = montype.color;
+        pick_a_monster.entries[i].extratxt.left = 1;
+        ++i;
+        mtypes.push_back( &montype );
+    }
+}
+
+void debug_menu::wishmonstergroup( tripoint_abs_omt &loc )
+{
+    bool population_group = query_yn(
+                                _( "Is this a population-based horde, based on an existing monster group?  Select \"No\" to manually assign monsters." ) );
+    mongroup new_group;
+    // Just in case, we manually set some values
+    new_group.abs_pos = project_to<coords::sm>( loc );
+    new_group.target = new_group.abs_pos.xy();
+    new_group.population = 1; // overwritten if population_group
+    new_group.horde = true;
+    new_group.type = GROUP_ZOMBIE; // overwritten if population_group
+    if( population_group ) {
+        uilist type_selection;
+        std::vector<mongroup_id> possible_groups;
+        int i = 0;
+        for( auto &group_pair : MonsterGroupManager::Get_all_Groups() ) {
+            possible_groups.emplace_back( group_pair.first );
+            type_selection.addentry( i, true, -1, group_pair.first.c_str() );
+            i++;
+        }
+        type_selection.query();
+        int &selected = type_selection.ret;
+        if( selected < 0 || static_cast<size_t>( selected ) >= possible_groups.size() ) {
+            return;
+        }
+        const mongroup_id selected_group( possible_groups[selected] );
+        new_group.type = selected_group;
+        int new_value = 0;
+        query_int( new_value, _( "Set population to what value?  Currently %d" ), new_group.population );
+        overmap &there = overmap_buffer.get( project_to<coords::om>( loc ).xy() );
+        there.debug_force_add_group( new_group );
+        return; // Don't go to adding individual monsters, they'll override the values we just set
+    }
+
+
+    wishmonstergroup_mon_selection( new_group );
+    overmap &there = overmap_buffer.get( project_to<coords::om>( loc ).xy() );
+    there.debug_force_add_group( new_group );
+}
+
+void debug_menu::wishmonstergroup_mon_selection( mongroup &group )
+{
+
+    std::vector<const mtype *> mtypes;
+    uilist new_mon_selection;
+    setup_wishmonster( new_mon_selection, mtypes );
+    wish_monster_callback cb( mtypes );
+    new_mon_selection.callback = &cb;
+    new_mon_selection.query();
+    int &selected = new_mon_selection.ret;
+    if( selected < 0 || static_cast<size_t>( selected ) >= mtypes.size() ) {
+        return;
+    }
+    const mtype_id &mon_type = mtypes[ selected ]->id;
+    for( int i = 0; i < cb.group; i++ ) {
+        monster new_mon( mon_type );
+        if( cb.friendly ) {
+            new_mon.friendly = -1;
+            new_mon.add_effect( effect_pet, 1_turns, true );
+        }
+        if( cb.hallucination ) {
+            new_mon.hallucination = true;
+        }
+        group.monsters.emplace_back( new_mon );
+    }
+}
+
 void debug_menu::wishmonster( const std::optional<tripoint> &p )
 {
     std::vector<const mtype *> mtypes;
 
     uilist wmenu;
-    wmenu.desired_bounds = { -1.0, -1.0, 1.0, 1.0 };
-    wmenu.selected = uistate.wishmonster_selected;
+    setup_wishmonster( wmenu, mtypes );
     wish_monster_callback cb( mtypes );
     wmenu.callback = &cb;
 
-    int i = 0;
-    for( const mtype &montype : MonsterGenerator::generator().get_all_mtypes() ) {
-        wmenu.addentry( i, true, 0, montype.nname() );
-        wmenu.entries[i].extratxt.txt = montype.sym;
-        wmenu.entries[i].extratxt.color = montype.color;
-        wmenu.entries[i].extratxt.left = 1;
-        ++i;
-        mtypes.push_back( &montype );
-    }
-
     do {
         wmenu.query();
         if( wmenu.ret >= 0 ) {