Gastrodon

“It has a pliable body without any bones. If any part of its body is torn off, it grows right back.”

— Pokémon Diamond

“It apparently had a huge shell for protection in ancient times. It lives in shallow tidal pools.”

— Pokémon Pearl

“Long ago, its entire back was shielded with a sturdy shell. There are traces of it left in its cells.”

— Pokémon Platinum