Go here and check out the story of Otto the octopus. It amuses me that they had to do a stake out of his enclosure to figure out how he was doing it. He also periodically rearranges his tank to better suit his taste. People often do not give creatures such as these enough credit. They are much more intelligent than most people think. I did find the website for the aquarium where Otto lives, but it wasn't in English, so I didn't link to it.