Zombie ball and Corpse beetle.

data/json/monstergroups/bugs.json

@@ -65,5 +65,11 @@
       { "monster": "mon_graboid", "freq": 30, "cost_multiplier": 20 },
       { "monster": "mon_halfworm", "freq": 0, "cost_multiplier": 0 }
     ]
+  },
+  {
+    "type": "monstergroup",
+    "name": "GROUP_BEETLE",
+    "default": "mon_corpse_beetle",
+    "monsters": [  ]
   }
 ]

data/json/monstergroups/zombies.json

@@ -549,7 +549,10 @@
     "name": "GROUP_PLAIN",
     "type": "monstergroup",
     "default": "mon_zombie",
-    "monsters": [ { "monster": "mon_zombie", "freq": 40, "cost_multiplier": 1 } ]
+    "monsters": [
+      { "monster": "mon_zombie", "freq": 36, "cost_multiplier": 1 },
+      { "monster": "mon_zombie_ball", "freq": 4, "cost_multiplier": 6 }
+    ]
   },
   {
     "name": "GROUP_HOTEL_POOL",

data/json/monsters/insect_spider.json

@@ -1142,5 +1142,35 @@
     "death_function": [ "NORMAL" ],
     "special_attacks": [ { "type": "leap", "cooldown": 4, "max_range": 4, "allow_no_target": true }, [ "EAT_CROP", 120 ] ],
     "flags": [ "SEES", "HEARS", "SMELLS", "CLIMBS", "LARVA", "STUMBLES", "PATH_AVOID_FIRE" ]
+  },
+  {
+    "id": "mon_corpse_beetle",
+    "type": "MONSTER",
+    "name": { "str": "corpse beetle" },
+    "description": "An oversized beetle.  It seems to have abnormal preference to eat zombies than anything else.",
+    "default_faction": "beetle",
+    "bodytype": "insect",
+    "species": [ "INSECT" ],
+    "volume": "50 L",
+    "weight": "90 kg",
+    "hp": 90,
+    "speed": 70,
+    "material": [ "flesh" ],
+    "symbol": "C",
+    "color": "red",
+    "aggression": -10,
+    "morale": 0,
+    "melee_skill": 4,
+    "melee_dice": 2,
+    "melee_dice_sides": 6,
+    "melee_cut": 0,
+    "dodge": 0,
+    "armor_bash": 12,
+    "armor_cut": 12,
+    "vision_day": 10,
+    "harvest": "arachnid",
+    "anger_triggers": [ "FRIEND_ATTACKED" ],
+    "death_function": [ "NORMAL" ],
+    "flags": [ "SEES", "HEARS", "SMELLS", "CLIMBS", "PATH_AVOID_FIRE" ]
   }
 ]

data/json/monsters/zed_fusion.json

@@ -230,5 +230,35 @@
     "harvest": "exempt",
     "death_function": [ "NORMAL" ],
     "flags": [ "SEES", "HEARS", "SMELLS", "IMMOBILE", "WARM", "POISON", "IMMOBILE", "NO_BREATHE", "FILTHY" ]
+  },
+  {
+    "id": "mon_zombie_ball",
+    "type": "MONSTER",
+    "name": "zombie ball",
+    "description": "Something pressed that bunch of zombies into giant ball.  It seems they are stuck, unless something else moves them.",
+    "default_faction": "zombie",
+    "volume": "300 L",
+    "weight": "500 kg",
+    "species": [ "ZOMBIE", "ABERRATION" ],
+    "diff": 0,
+    "hp": 150,
+    "speed": 25,
+    "material": [ "flesh" ],
+    "symbol": "O",
+    "color": "red_green",
+    "aggression": 100,
+    "morale": 100,
+    "melee_skill": 1,
+    "melee_dice": 5,
+    "melee_dice_sides": 2,
+    "melee_cut": 0,
+    "vision_day": 30,
+    "vision_night": 30,
+    "armor_bash": 15,
+    "armor_cut": 15,
+    "regenerates": 10,
+    "harvest": "zombie",
+    "death_function": [ "NORMAL" ],
+    "flags": [ "SEES", "HEARS", "SMELLS", "IMMOBILE", "WARM", "POISON", "NO_BREATHE", "FILTHY" ]
   }
 ]