Kraken

The Kraken is a monstrous, miles-long squid-like beast that only emerges from the ocean's depths once every thousand years. It then floats on the surface, covered with barnacles and appearing to be an island, until some foolish ship comes too close and is destroyed by the violent sea monster. Almost no one escapes a Kraken attack, as the monster swiftly crushes the entire ship. The Kraken may have a nautaloid shell, shoots clouds of ink with the force of a nuclear bomb, and has hourglass-shaped pupils. Due to the fact that they hibernate most of their lives, they rarely reproduce, and as such there are usually a half-dozen or less Krakens alive at a time. Each Kraken may live for 10,000 to 15,000 years and be one to eight miles in size.