Basic ability to create a 'stage' for a boss fight, which is a thing in front the boss animates behind.

assets/bosses.json

@@ -1,7 +1,11 @@
 {
   "RAT_KING": {
     "components": [
-      {"_type": "BossFight", "background": "boss_fight_background", "weapon_sound": "Sword_Hit_2"},
+      {"_type": "BossFight",
+        "background": "boss_fight_background",
+        "stage": "none",
+        "weapon_sound": "Sword_Hit_2"
+      },
       {"_type": "Combat", "hp": 20, "max_hp": 20, "damage": 20, "dead": false},
       {"_type": "Animation", "easing": 3, "ease_rate": 0.2, "simple": false, "frames": 2, "speed": 0.02, "scale": 0.2},
       {"_type": "Sprite", "name": "rat_king_boss", "width": 720, "height": 720, "scale": 0.8, "stationary": false},
@@ -12,6 +16,7 @@
     "components": [
       {"_type": "BossFight",
         "background": "devils_fingers_background",
+        "stage": "none",
         "weapon_sound": "Sword_Hit_2"
       },
       {"_type": "Combat", "hp": 20, "max_hp": 20, "damage": 20, "dead": false},

assets/config.json

@@ -48,7 +48,10 @@
     "down_the_well": "assets/down_the_well.jpg",
     "boss_fight_background": "assets/rat_king_boss_fight_background.jpg",
     "devils_fingers_background": "assets/devils_fingers_background.jpg",
-    "devils_fingers_sprite": "assets/devils_fingers_sprite.png"
+    "devils_fingers_sprite": "assets/devils_fingers_sprite.png",
+    "devils_fingers_stage": "assets/devils_fingers_stage.png",
+    "tunnel_with_rocks": "assets/tunnel_with_rocks.png",
+    "tunnel_with_rocks_stage": "assets/tunnel_with_rocks_stage.png"
   },
   "worldgen": {
     "enemy_probability": 80,