“What’s black as tar, has armored scales and a mouth full of teeth?” the institute asked in a June 22 Facebook post. “A melanistic longnose gar!” Put simply, the creature was a known fish with a rare and disconcerting abnormality. Longnose gar are typically a “tan-olive color, with brown spots,” but this one had darkened into something that would be virtually invisible in the murky 170-mile river.