(CNN) -- A 19-year-old Florida teen didn't think twice about jumping on a 30-foot, 50,000 pound whale shark in the Gulf of Mexico.
The video shows Chris Kreis jumping off the back of his boat and latching onto the dorsal fin.
The ride was short-lived and only lasted about 10 seconds.
Some marine biologists, however, are less enthused about the incident.
They say the fish could have attacked Kreis, and that human contact can potentially harm the fish by removing part of its protective coat.
Whale sharks are the ocean's largest fish and feed mostly on plankton.