Visitors to Big Bend National Park in far West Texas have been a little on edge since one of its many animal inhabitants went viral online, spawned national news stories, and was called a “land lobster from hell” by Chron.com.

It all started when the park’s Facebook page shared a photo on July 14 of what appears to be an enormous scorpion-spider hybrid with lobsteresque pincers, with an educational caption helpfully explaining that these acid-spraying creatures, called vinegaroons, have emerged from their burrows “in search of food and love” after a bout of summer rain. 

“I am going to have nightmares from this photo,” wrote one of roughly 1,500 commenters. 

The following week, Big Bend National Park ranger Annie Gilliland was working at the front desk of the visitor’s center when a tourist came in demanding reassurance that they would not fall prey to the nightmarish internet sensation. “Someone came up with the picture on their phone and said, ‘What are these things? Are they gonna be in my campsite? I’m afraid,’” says Gilliland. “We calmed them down from that.” Prospective visitors began calling the park to ask if they were going to “see ‘land lobsters’ all over the place” (“That is a name I think [Chron.com] made up,” says Gilliland).

It turns out these so-called “land lobsters from hell” are arachnids—meaning they belong to the same class as spiders and ticks—and though they do have an alarming appearance, and can spray a mild vinegar solution as a defense mechanism, they are harmless to humans and mostly keep to themselves. “I would say some things got exaggerated,” says Gilliland of the onslaught of press attention. 

Also known as whip scorpions, vinegaroons are fairly common in the Big Bend region, which makes the sudden national alarmism all the more baffling for park employees. When I first called the park’s headquarters, a man answered the phone, listened to my brief journalistic spiel, and remarked dryly, “You want to do a story about a very common insect in the Big Bend called the vinegaroon?” (Technically, as I would later learn, arachnids are not insects.) Still, Gilliland tells me that visitors are unlikely to spot one—vinegaroons remain burrowed underground for much of the year and emerge only when the desert drought is interrupted by the region’s rainy season. Heavy rainfall coaxed the vinegaroons from their hiding places about two weeks ago, so there are more of them out and about now—the viral photo was taken by a parkgoer—but their aversion to heat and sunlight still keeps them mostly hidden during the daytime.

Though more than one hundred vinegaroon species roam the planet, including seven in the United States, just one resides in Texas: the giant whip scorpion (Mastigoproctus giganteus giganteus), which grows up to three inches long. West Texas is its preferred habitat—legendary frontier judge Roy Bean once named a town in its honor—but the creature has also been spotted in South Texas and the Panhandle.

Ross Winton, an invertebrate biologist with Texas Parks and Wildlife, broke down a vinegaroon’s anatomy for me. Unlike a true scorpion, it has no poison-filled stinger. It has eight legs (like all arachnids) but only uses six for walking, while the long and skinny front pair are used as antennae. Vinegaroons are nocturnal, so they use these antennae-legs for feeling around in the dark and sensing their prey. The large front pincers are not legs but mouthparts that have evolved over time, says Winton, and in the rear they have long, whiplike tails (hence the name “whip scorpion”). As for the origin of the name “vinegaroon,” Winton tells me there is a tiny gland where that tail meets the abdomen that stores an acid with a pungent vinegar odor; sensory glands on the vinegaroon’s tail let it know if it has brushed against something that may be a threat, at which point it sprays the acid in self-defense. 

But that shouldn’t alarm parkgoers, Winton insists—the acid, which wouldn’t spray farther than a foot or two, is meant to deter predators like raccoons or armadillos, but it won’t harm a person. “It’s more of an irritant,” he says. “It’s not like hydrochloric acid that’s going to burn a hole in your skin. There are some people who may get a little first-degree burn or redness, but it tends to dissipate. It’s pretty gaseous, so it’s not something that’s going to bore into your skin like in Alien or Predator.”

It should also be said that vinegaroons aren’t interested in fighting you anyway. They would far rather hang out under rocks, eat insects, and search for a vinegaroon mate. “They’re not super aggressive unless they’re provoked,” says Winton. “If someone’s poking them with a stick, they might get you with their pincers, but they’re not going to chase you down.” Plus, the invertebrate serves an important purpose—by feeding on undesirable insects like cockroaches, it helps keep those populations under control.

Vinegaroons are so unthreatening, in fact, that some people choose to keep them as pets. Allison Shafer of Tulsa is an enthusiast—she works at a pet store and owns snakes, wolf spiders, a tarantula, and a scorpion, in addition to two female vinegaroons she calls Lady and Big Lady (Big Lady is slightly larger than Lady). She was a little horrified to learn about the Texas-based vinegaroon panic. “A lot of news sites are fear-mongering about these things,” she says. Shafer took to the Big Bend Facebook page to defend the honor of the vinegaroon, and tells me that she lets the Ladies crawl up and down her arm; she has been sprayed with their acid, and claims it’s so benign she didn’t even notice until she smelled vinegar.

“The fact that people are all like, ‘Kill it with fire; destroy it,’ is absolutely ridiculous, because there’s no reason to act like that about a little bug that can’t even hurt you,” says Shafer. “It just looks scary. It’s just minding its own business, doing its thing, like someone else’s cat or dog.” To each her own! Though if you do want an adorable, acid-spraying arachnid as a pet, bear in mind that you’re forbidden from taking them out of national parks—keep a respectful distance, then try a pet store.

Correction: A previous version of this story stated that the term “land lobsters from hell” originated from the Houston Chronicle. It actually came from Chron.com, which operates separately