Ultra-sun: Its shell is filled with a thick liquid. All of the cells throughout its body are being rebuilt in preparation for evolution.Moon: Its shell is hard, but it’s still just a bug shell. It’s been known to break, so intense battles with it should be avoided.Alpha-sapphire: The shell covering this Pokémon’s body is as hard as an iron slab. Metapod does not move very much. It stays still because it is preparing its soft innards for evolution inside the hard shell.