diff --git a/data/mods/TEST_DATA/monstergroups.json b/data/mods/TEST_DATA/monstergroups.json
index a12e15d399bc2..26ef371891275 100644
--- a/data/mods/TEST_DATA/monstergroups.json
+++ b/data/mods/TEST_DATA/monstergroups.json
@@ -103,6 +103,11 @@
     "type": "monstergroup",
     "monsters": [ { "monster": "mon_test_shearable", "pack_size": [ 4, 6 ] } ]
   },
+  {
+    "name": "test_upgrades_multi_null",
+    "type": "monstergroup",
+    "monsters": [ { "monster": "mon_null" }, { "monster": "mon_test_zombie_cop", "pack_size": [ 4, 6 ], "starts": "2 days" } ]
+  },
   {
     "name": "test_upgrades_multi_late",
     "type": "monstergroup",
diff --git a/data/mods/TEST_DATA/monsters.json b/data/mods/TEST_DATA/monsters.json
index 68296dfa81d78..ef303663ae6af 100644
--- a/data/mods/TEST_DATA/monsters.json
+++ b/data/mods/TEST_DATA/monsters.json
@@ -94,7 +94,14 @@
     "weight": "81500 g",
     "hp": 100,
     "speed": 50,
-    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "PET_WONT_FOLLOW" ]
+    "flags": [ "SEES", "HEARS", "SMELLS", "ANIMAL", "PATH_AVOID_DANGER_1", "WARM", "PET_WONT_FOLLOW" ],
+    "upgrades": {
+      "half_life": 0,
+      "into_group": "test_upgrades_multi_null",
+      "multiple_spawns": true,
+      "spawn_range": 5,
+      "despawn_when_null": true
+    }
   },
   {
     "id": "dissect_mon_test_CBM",
diff --git a/doc/MONSTERS.md b/doc/MONSTERS.md
index 4e6b6e7336975..8c2cf53c552c7 100644
--- a/doc/MONSTERS.md
+++ b/doc/MONSTERS.md
@@ -519,6 +519,7 @@ The upgrades object may have the following members:
 | `age_grow`   | (int, optional) Number of days needed for monster to change into another monster. Does not scale with the evolution factor.
 | `multiple_spawns` | (bool, optional) If using `into_group`, the selected entry spawns a number of monsters based on the entry's `pack_size`.
 | `spawn_range` | (int, optional) Mandatory when `multiple_spawns` is true. Determines how far away from the original monster the upgraded monsters can spawn.
+| `despawn_when_null` | (bool, optional) For `into_group`, when `mon_null` is selected as the group entry upgrade, the monster will despawn leaving no trace when this is true. Otherwise the monster "dies" naturally. Defaults to false.
 
 ## "reproduction"
 (dictionary, optional)
diff --git a/tests/mongroup_test.cpp b/tests/mongroup_test.cpp
index 69aafbba1c729..99a5a4a4ebd65 100644
--- a/tests/mongroup_test.cpp
+++ b/tests/mongroup_test.cpp
@@ -391,4 +391,23 @@ TEST_CASE( "mongroup_multi_spawn_restrictions", "[mongroup]" )
         CHECK( counts.count( mon_test_shearable ) > 0 );
         CHECK( counts.count( mon_test_zombie_cop ) > 0 );
     }
+
+    SECTION( "no valid spawns, with mon_null" ) {
+        std::map<mtype_id, int> counts;
+
+        test_multi_spawn( mon_test_CBM, 5, 4, 6, calendar::turn_zero + 1_days,
+        { mon_null, mon_test_CBM, mon_test_zombie_cop }, counts );
+
+        CHECK( counts.empty() );
+    }
+
+    SECTION( "1 valid spawn, with mon_null" ) {
+        std::map<mtype_id, int> counts;
+
+        test_multi_spawn( mon_test_CBM, 5, 4, 6, calendar::turn_zero + 4 * 3_days + 12_hours,
+        { mon_null, mon_test_CBM, mon_test_zombie_cop }, counts );
+
+        CHECK( counts.size() == 1 );
+        CHECK( counts.count( mon_test_zombie_cop ) > 0 );
+    }
 }