A Florida teen is at the center of a controversy this week after friends filmed him hopping onto the back of a 30-foot whale shark and "riding it" for several seconds.
The stunt, which took place in the Gulf of Mexico last week, occurred when the 19-year-old spotted the enormous animal while fishing west of Captiva Island, according to NBC Miami.
Kreis promptly jumped off the fishing boat and onto the shark's back, grabbing hold of its dorsal fin and briefly "riding" the fish until it began to descend, according to CBS affiliate WUSA9
The largest fish in the ocean, according to National Geographic, whale sharks can grow to 40 feet long on a diet of plankton and small fish.
Kreis said he was motivated to take the plunge by what he felt was a unique opportunity.
"It went through my mind, yeah, I might not be able ever to do it again," Kreis told NBC. "So I did it. It was incredible."
Some marine biologists, however, are less enthused about the incident.
Biologist Bruce Neill told NBC Miami that the fish could have attacked Kreis, and that human contact can potentially harm the fish by removing part of its protective coat of slime.
While there have been several high-profile examples of the trouble you can get into for disturbing Florida's manatee population, it is not illegal to ride whale sharks noted ABC News.