article: 24 July 2017 Last updated at 14:56 BST He's been racing sharks... Yes, you read that right. Michael Phelps had a special shark suit to help him compete against the ocean predator. And don't worry - he actually wasn't in the water with them, it was done with special effects. Watch this to see who was the fastest... Pictures courtesy of Discovery
summary: Olympic superhero Michael Phelps is one of the fastest swimmers on Earth, but he's been taking up a pretty weird challenge.