In a comic book universe, either a scientific explanation for King Shark or a supernatural one are equally plausible, but neither has been specifically confirmed in DC lore.
I am curious to see how (or even if) this conundrum will be addressed by King Shark’s storyline in The Suicide Squad, as well how they may explain his reason for joining the titular crew.
After their shared experiences in opposition of King Shark, Honolulu-based FBI agent Sam Makoa would reluctantly develop a respect for Superboy, to whom he would explain that the aquatic humanoid was nothing more than some strange “savage mutation” – similar to 2016’s Suicide Squad character Killer Croc – without any mystical origins.
A 1999 issue of Superboy would even imply that he is a Wild Man, which DC Comics fans may recognize as a type of genetically evolved, anthropomorphic animal being much like the creatures from The Island of Dr. Moreau – a classic sci-fi novel by H.G. Wells.