Fish biologists have explained this demon … but there’s no fix for the nightmares.

On Thursday, Reddit user “StuffyUnicorn” posted a video that’s sure to haunt the minds of all who look upon it. The grotesque footage shows a fish that appears to have two heads, complete with four eyes and a pair of enormous gaping mouths.

Besides feeling disturbed — comments included “That is one of the most unsettling things I have ever seen,” and “Reminds of that one part in The Thing” — people really wanted to know what had caused this bizarre phenomenon. Was the fish a conjoined twin? Maybe it lived near a nuclear plant, some said, and had been affected by a weird mutation.

Fish biologists weighed in to set our minds at ease. First of all, they determined that this is probably an Asian carp (specifically, an Asian carp of either the bighead or silver variety). Under normal circumstances, the carp would look something like this:

Bighead Carp
The bighead carp, a species of Asian carp.

But these are not normal circumstances. We live in a dark, cruel world, in which a fish can end up like this:

The video of the carp posted on Reddit.

So what’s going on with this poor carp?

All is not as it seems: As it turns out, the fish doesn’t actually have two heads. It’s just extraordinarily deformed — though it’s unclear whether that’s due to an improperly-healed injury or a genetic mutation.

The “eyes” at the top are actually nostrils (the Asian carp’s eyes are set very low on its face):

Those are nostrils at the top.

And the “mouth” at the bottom, in the words of user “mr_canoehead,” is “is just a hole that has formed due to the gill arches not being connected to the lower jaw.”

That's a second hole at the bottom; the carp probably got torn somehow.

This hole probably came about from an injury. Somehow the gill arches got dislocated from the lower jaw and tore open the carp’s flesh; it could have been ripped apart by a fisherman’s hook.

What does this deformity mean for the fish’s future? Well, first of all, “StuffyUnicorn” didn’t disclose whether he kept the fish or threw it back into the water. Our mutant friend may already be flayed, grilled, and sitting at the bottom of several stomachs.

But if the carp went back into the water, the chances of it surviving for a while longer are quite good. An abnormality like this might have made it a target for predators when it was very young, but it’s large enough now to probably avoid that (there also aren’t many natural predators for this carp in the United States). The injury itself may ultimately shorten the carp’s lifespan, but as “BaylisAscaris” assessed, “I’ve seen this before, and fish can live a long time with it.”

Unfortunately, the gaping hole doesn’t really act as an additional spot for plant and animal plankton to flow into the fish’s body. The Asian carp is a filter feeder, so it gets its food by pumping water over its gill rakers (the bony suspensions that project from the gill arches), and those rakers only exist in its real, top mouth. Actually, the hole will mostly just cause the carp to lose a lot of ingested food.

This carp won’t be leading an ideal existence for the rest of its days, but at least it’s a truly special creature and is getting a taste of fishy fame.

Photos via Flickr / Asian Carp Regional Coordinating Committee, Reddit user: StuffyUnicorn, Reddit User: StuffyUnicorn