Justin Schmidt is an entomologist, and has accordingly been stung by a lot of bugs. So he invented something called the Schmidt sting pain index (named after some guy called Schmidt, apparently), which ranks the pain of insect stings from one to four. Down at one is something like the fire ant, which is so named for a reason, while up at four is the bullet ant, which is so called for a very, very good reason.

Joining the bullet ant at four is a critter that lives right here in the southwestern US: the tarantula hawk. It’s actually a kind of solitary wasp with a sting whose resulting pain only lasts three minutes, but it’s so fiercely electric that it could only be described as totally unacceptable. "There are some vivid descriptions of people getting stung by these things,” says invertebrate biologist Ben Hutchins of Texas Parks and Wildlife, “and their recommendation—and this was actually in a peer-reviewed journal—was to just lie down and start screaming, because few if any people could maintain verbal and physical coordination after getting stung by one of these things. You're likely to just run off and hurt yourself. So just lie down and start yelling."

Tarantula hawk Joao Paulo Burini/Flickr Open/Getty Images

That paper, as it happens, was written by our friend Schmidt, and is probably the most unintentionally hilarious scientific paper I’ve ever read. He recounts one enterprising scientist who netted 10 tarantula hawks—and of course reached in to grab them: “Undeterred after the first sting, he continued, receiving several more stings, until the pain was so great he lost all of them and crawled into a ditch and just bawled his eyes out.”

Which is why folks in Texas have seemed a bit...worried over the past few weeks, as numbers of the things are on the rise. In reality, though, there’s nothing to be worried about here (trust me). The tarantula hawk is in fact a brilliant parasite that attacks tarantulas, not humans, paralyzing them with a sting before dragging them into a den. Here it lays an egg that hatches into a larva and devours the paralyzed spider alive—over the course of several weeks.

Tarantula Hawk (Pepsis sp), a giant wasp, confronts Tarantula in a sequence where the spider is paralyzed and parasitized by wasp's eggs, Riverside, California Minden Pictures/Getty Images

So take heart, dear Texans. You’d have to try real hard to get stung by these things, like picking them up or stepping on them. Quite frankly, they don’t seem to pay people no mind, even if approached, probably because they know they could kick human asses all over the place. “The tarantula hawks are really bold in terms of wasps,” says Hutchins. “Researchers think that's because they have very few natural predators. They have such an effective deterrent mechanism, and that's their really painful sting.” Indeed, there are almost no reports of any animal dumb enough going after these things.

Accordingly, there’s not much to stop them when their numbers start climbing, like they are right now in Texas. Thanks to a strong rainy season, vegetation is doing quite well, and when vegetation does quite well, so do insects. The tarantula hawk is actually a nectar-feeder, not a carnivore, so it’s in fat city these days.

But not all of these wasps sting: The males can’t do it at all. This is because stingers in the insect world belong to the females (the structures evolved from ovipositors, which the females use to lay eggs). So in lovely conditions such as these, males will hang out on flowers and wait for the females to come around and mate. The female then flies off—and this is where the real fun begins.

Except for the tarantulas. They’re not going to like this one bit.

Sting Operation

Unlike a lot of insects, the fertilized female won’t just be depositing her eggs somewhere and flying off, hoping they’ll survive on their own. Nope, she finds an unwitting caretaker first: specifically, any number of tarantulas that are also good and active during these times of plenty.

The she-wasp has to be careful, because while she's pretty darn big, the tarantula can be several times bigger than her. And although tarantulas may be harmless to humans, they have massive fangs that could do a number on the wasp. “The tarantula hawk will kind of approach the tarantula,” says Hutchins, “back away, approach, and then go in and actually get in underneath the tarantula and then flip it over, and then sting it. She's usually looking for a chink in the tarantula's armor, and that's often at the joints in the legs.”

And she’s really good at it. One survey found that in 400 battles, only a single wasp perished. But that isn’t to say the tarantulas weren’t putting up a good fight. In his sneakily comic scientific paper, Schmidt notes that researchers have reported “violent encounters, often hearing loud crunching or snapping sounds as the spider has the wasp in its jaws, and with spiders frequently losing legs during the encounters.” It seems that the tarantula hawks’ hard, smooth exoskeletons may crunch a bit, but they still save their owners from death.

BY1F3B Tarantula hawk wasp dragging a giant spider Gustavo Mazzarollo/Alamy

As for the tarantulas, well, they almost never escape. The sting paralyzes the spider nearly instantly, allowing the wasp to drag it into a pre-dug burrow or back to the tarantula’s own den. Here it drops the victim and lays a single egg on it, then leaves and seals the chamber behind it. The egg hatches into a larva, which starts eating the still-paralyzed spider, focusing on non-essential tissues to keep it alive for as long as possible—perhaps weeks.

That there is one hell of a head start in life for the kiddo. It’s a striking contrast to the lives of social wasps, which collectively care for their young without encouraging them to devour paralyzed tarantulas. And indeed, this manifests in the wasps’ venom itself. Typically, the venom of social wasps tends to be both painful and damaging to tissue, whereas the tarantula hawk’s is all agony and no damage. This is likely because social wasps have a queen and young to protect from their enemies, so simply inflicting pain may not do the trick—the target may be down, but not out. In contrast, the tarantula hawk is a lone wolf, looking out only for itself. All it has to do is stun its attacker and make a getaway.

Sure, every so often it’s an unfortunate human on the receiving end of that stinger, but the tarantula hawk is far more placid than it may let on. “Even though they do have a really painful sting, in my opinion they're just a really cool component of our fauna,” says Hutchins. “People don't really need to be afraid of them, and indeed I think they're really cool to just sit and watch them in your yard.”

But should you get stung, just remember to stop, drop, and scream like no one’s listening.

Browse the full Absurd Creature of the Week archive here. Know of an animal you want me to write about? Are you a scientist studying a bizarre creature? Email matthew_simon@wired.com or ping me on Twitter at @mrMattSimon.