If you could be anything you wanted to be besides being a human, what would you want to be and why?

A dolphin.

"On the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much - the wheel, New York, wars and so on - while all the dolphins had ever done was muck about in the water having a good time. Conversely, the dolphins had always assumed that they were more intelligent than man - for precisely the same reasons."
- Douglas Adams, The Hitch-hiker's Guide to the Galaxy

God. Because it would be fun to screw up humanity.

A SUPER human