Swimmer Adam Walker was looking to raise funds for Stop Whaling, a nonprofit group focused on whale and dolphin conservation.  He didn't expect to encounter any sharks, but to his dismay -- one swam up right near him!  That's when something incredible happened.

A pod of dolphins swam up and surrounded him. The group of about 10 stayed with him for an hour until the shark left.  That's what I call returning the favor.  Check out this incredible video.