Surume

The Kraken is a massive octopus creature from Norse mythology. The Strawhats first encountered one on their way to Fishman Island. Apparently they feed on ships. Caribou recites a story about, calling it "the enemy of the human race". Luffy apparently doesn't consider the one encoutered in chapter 604 a threat, as he says he is gong to tame it and refering to it as "that little guy" - despite the fact that the Kraken in question is at least several dozen times larger than the Thousand Sunny.