Ameboid

Ameboid is an enemy that could be found at the gate from Smithy's Factory in Super Mario RPG: Legend of the Seven Stars. It has low HP, but if Mario and company fail to defeat in a single attack, the Ameboid splits into five with the same stats as the original. Outside of battle, they are merely blue spots that become bigger, and only reveal themselves to be Ameboids when they are approached. They are strong against jump attacks and weak against fire.

Chesters body appears to be a tan-colored Ameboid contained with its treasure chest-like exterior.