This is a Lego Bionicle 8917 Set, Mahri Nui Barraki Kalmah. This is Lego Item 4498055.
Cunning and brutal, Kalmah strikes fear into the hearts of the fiercest sea beasts. His tentacle can crush his foes, or he can use his sea squid launcher to drain their life force. The tentacles on the back of his head help him to sense surprise attacks before they happen. Commanding an army of giant squid, Kalmah may be impossible to stop. 53 pieces.