Mysterious Abyss

The Mysterious Abyss keyblade is acquired after defeating Ursula and completing Atlantica in Kingdom Hearts II. This Keyblade is the equivalent of the Crabclaw Keyblade from Kingdom Hearts. This is one of the few opitional Keyblades' in the game. To get it you have to do the singing mini games in Atlantica.

Appearence
The Keychain is in the shape of a shell connected to the handle which is made up of assorted shells by a golden chain. Whilst the teeth of the Keyblade are in the shape of a wave.