Its just a thought, I saw when meowth looked under and the shape of the bottom of the costums and when meowth looked under its costume it seemed to look more like some kind of toxic-ish smoke. so I basically designed this concept art based on what the pokedex entries are saying about it. Also you would notice until its hit during battle the head will fall. it stays up mostly due to the weirdly shaped stem on its actual head.
hope you enjoy! (its actually kinda cute :3)