While we wonder about what exotic and potentially hostile alien species might be out in the galaxy, there are plenty of terrifying creatures right here at home.

Exhibit A: The tongue-eating louse, who makes a career out of devouring a victim’s tongue before trying to replace it altogether. If Clive Barker or Stephen King thought up a fish parasite, this would be it.

This horror of nature was recently featured in a Facebook post by the Galveston Island State Park in Galveston, Texas, where it showed off a photo of the parasite lodged inside a fish’s mouth.

(Image courtesy of the Texas Parks and Wildlife Department)

The louse, or Cymothoa exigua, is an isopod, or crustacean. It typically enters the fish (usually the Atlantic croaker, sea trout, or snapper) through its gills and seeks to sever the blood vessels in the tongue, eating the blood until the tongue dies off.

It then settles in the fish’s mouth, where it can subsist on a steady diet of fish mucus and more blood. Some feed on the same fish, causing it to become malnourished. If a female louse is present, it can mate with males inside the mouth.

While it doesn’t kill the fish, it would appear to make their existence annoying at best and hellish at worst.

According to the park, it’s the only parasite that can replace a host’s organ.

Fortunately, it doesn’t target humans. Not physically, anyway. Psychologically, it’s another story. Or, as Coastal Fisheries Science Director Mark Fisher told KSAT in Texas: “It can be a surprise to peer into a fish’s mouth and have another set of eyes looking back at you.”

[h/t NPR]