Shelluno (シェルーノー Sherūnō) is an enemy from Mega Man Zero 3 based on a clam. When Zero 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 and Volteel Biblio's stage, the Submerged Library.
In addition, there is yellow variety that only appear in the "Pokie Pokie the Fishies" Minigame with low probability.