Giant Mollusk

Giant Mollusk (巨大軟休生物) was a monster native to the New World.

Appearance
Similar to an octopus it has eight tentacles.

Abilities
A many tentacled beast that has the ability to mimic and blend in with its surroundings making itself seemingly invisible. In addition to that, it was strong enough to tear a ship in two.

Trivia

 * In the Mass for the Dead game, one of these creatures dwelt in a hidden cave on a deserted island where a wrecked pirate ship was located. The Pleiades while on a vacation/mission were attacked by it when they discovered the cave.