I think its safe to say that this cat has made a friend for life in this really cool video uploaded by n24our on March 6, 2011:
That cat looks a lot like my little buddy (Buster). However, I suspect Buster would run like hell if some giant, fish-like critter approached him. And yes, I know that dolphins are mammals. Its just the whole swimming/fin thing. Buster wouldn't know the difference. The only type of aquatic creature he's ever been exposed to comes out of a can.