Player-controlled mice spawn next to a vent by default, spawn at MOB_LAYER, can nibble food to regain health, can pass through plastic flaps, and can climb into disposal units.

Mice cannot pull objects.

code/modules/reagents/reagent_containers/food/snacks.dm

@@ -196,6 +196,10 @@
 				if(sattisfaction_text)
 					M.emote("[sattisfaction_text]")
 				del(src)
+		if(ismouse(M))
+			var/mob/living/simple_animal/mouse/N = M
+			N.emote("nibbles away at the [src]")
+			N.health = min(N.health + 1, N.maxHealth)
 
 
 ////////////////////////////////////////////////////////////////////////////////