What Was That ???

A friend send me this video and reminded me to watch it. Obediently, I click on the link, hoping its not one of those dumb prank videos where a horror picture suddenly appear at the end of the video.

What greeted me was something unexpected. Its a sea creature. And never in my life did I see such creature before. Does anybody know what this creature is? I wonder if this creature is in wikipedia. How do I refer to wiki if I don't know the name of this creature?

Here is the video. This creature looks weird and 'vulgar' when flipped over. And it was bigger than I though. At the end of the video...something unexpected happened and I couldn't help but to...LAUGH!