Cuttlefish, Octopus, Squid, I don't really care... They are too awesome.

On second thought, I do care. A Flamboyant Cuttlefish (they're poison and purple!) or a Mimic Octopus, please. Cuttlefish are social with one another, and less destructive than octopi... and they have the added benefit of a Cthulhu-like visage! ^_^

*cuddles the cuttlefishes