This 'alien fish' came from the ocean, not outer space

"What was it? Where did it come from? Who are the all-powerful creatures it brought from outer space? And what do they want on Earth?" a trailer for "It Came From Outer Space" said.

Pisces Sportfishing Fleet posted the images to Facebook, and users took their own guesses.

The fisherman, a high school senior from Chicago on a fishing trip with his dad, told the Chicago Tribune, "I asked our guide what it was, and he said he had never seen anything like it in 25 years of doing this."

But a later update from the same group gave a possible explanation — the "alien fish" is actually an albino swell shark.

In the picture, the captured fish's stomach is completely swollen, which, as its name suggests, is a common practice for this creature to ward off predators.

The rare shark was eventually released into the ocean to continue its long, strange life.

This video includes clips from YouTube / ProfessorRamey and "It Came From Outer Space" / Universal Pictures, and images from Facebook / Pisces Sportfishing Fleet and City.and.Color / CC BY 2.0.