Lobsters molt their exoskeletons as they grow. As this video demonstrates, it's an amazing process to watch. The lobster gradually shucks its carapace, breaking free at the end.
Rocket News 24 says that this video was shot at a seaside inn in Japan. The staff had planned to cook the fellow, but they noticed that he was about to molt. They took him out of the tank to observe.
UPDATE 12/8/14: The video has been pulled down. That's unfortunate. Heere's another one that shows the same process.
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