Shark n' Roll - S1.E6

When a musician called Melvin Kresnik accidentally digests contaminated popcorn and water that was tainted with a gene-slamming chemical, he becomes a mako shark later known as Rox and befriends the Street Sharks. Together, they have to save the concert in town and its attendants from being mutated into more sea creatures through the same way that Rox was mutated.