Shelluno

Shelluno (シェルーノー) is an enemy from Mega Man Zero 3 based on a clam shell. When ZeroXorZ is facing a Shelluno, it closes its shell and is invulnerable while closed. When Zero faces to opposite side or faces it for a long time, it will open and swim in his direction to attack. Shelluno appears in Childre Inarabitta's stage, the Oceanic Highway Ruins.