Bivacle

Bivacle is a Water/Rock-type Fakemon that appears in the fan game Pokémon Obsidian by Atomic Reactor.

It evolves from the Pokémon Shellder, and evolves into Cuttacle starting at level 36.

Dex Entry
Once a Shellder clamps on to a Slowpoke's tail, the nutrients in the tail trigger an alternate evolution for Shellder.