Kraken

When they chained the sea-thing we all knew it wouldn't hold. A flick of its great winding limbs would break the chains, or else the foulness it exuded would slip it free or eat the links away. It would roar and drive men mad until they loosed it and offered themselves as the first to be devoured. But we were wrong. It sank to the seafloor with the weight of all that iron, and there it lay, whimpering. We watched it there, until it was gone. And that was the end of us.