Down in Baja California there crawls a beast so bizarre, so cruel, so foul, that the mere mention of it sends locals scurrying. It’s an opportunist, said to attack humans at their most vulnerable moment: potty time.

Should you be foolish enough to drop trou and answer the call of nature in the wilderness, you’ll find the beast will “enter your body by the most unspeakable means,” said Carl Franklin, a herpetologist at the University of Texas at Arlington. “And it’ll rip your guts, shred them to pieces.” The death is slow, not to mention embarrassing.

OK, it’s not true—the creature, a reptile called the Mexican mole lizard, is in fact totally adorable and completely harmless—but it sure is a powerful myth. A few years ago Franklin was driving through Baja with his wife searching for the critters, and pulled up to two cowboys. He handed them a picture of the mole lizard and asked if they’d seen any lately, and “they just twisted up their faces in disgust, and they went over and saw my license plate is from Texas.” They then proceeded to admonish him for coming to their country for such things.

“I get to the next town, 10 miles away,” Franklin recalls, “and I see a young guy walking on the side of the road and I stop and I ask him and he just starts backing up, and he says, ‘Hey mister we're all really good people here. My uncle just called me and told me you were coming.’”

The Mexican mole lizard eats just about anything small enough and soft enough. Except ice cream. It never really comes across ice cream. Carl Franklin

Which is all to say, finding Mexican mole lizards is hard on its own—they're about the size of a large earthworm—and much more so when you’ve alienated the locals. Regardless, this is one of the strangest, most mysterious reptiles on Earth (it technically isn’t a lizard or a snake, but sits in a category all its own, the amphisbaenians), with powerful front limbs and rear limbs that have vanished save for vestigial bones you can only make out on X-rays. Strangely, the three species of Mexican mole lizard are the only amphisbaenians that haven’t lost all their limbs entirely. Why that is, no one is quite sure. Stranger still, each species has a different number of fingers: one with three, another with four, and the last with five.

Part of the problem with finding these things is that they’re subterranean, burrowing through sandy soil with their reinforced heads while scooping back debris with those well-developed claws. It’s no wonder, then, that they’ve lost their back legs. Often in evolution it makes sense for a structure to evolve away if it's no longer useful, or indeed a detriment, sparing you the energy and resources and time needed to build it. As a bonus, what you don’t have can’t get injured—or in the case of the Mexican mole lizard's hind limbs, perhaps losing lose legs means you can move better through the soil.

The creature's eyes are quite beady and underdeveloped. “If you're basically a mute inhabitant in a dark underworld, you gotta figure that touch and taste and smell are going to be the three keen senses,” said Franklin. “So anything like vibrations, they certainly can feel, but finding mates and even locating prey, it’s going to be chemosensory” cues, which they pick up with their tongue.

Carl Franklin

And as for prey, these critters are going after pretty much anything soft they can get their tiny conical teeth on: a whole range of small insects, as well as things like cockroach eggs—and good on 'em for that. Franklin may be the only person in the world who has legally obtained them to raise in captivity, and he can attest that they’ll happily eat things that don’t even live with them in the wild, including earthworms. “I swatted a little spider one day and tossed it in,” he said. “They ate everything except for his fangs. So why that wasn't eaten, I don't know. Maybe they could smell it and decided it wasn't tasteful.”

Mexican mole lizards spend so much time underground in search of food that they lack the melanin that gives organisms their color. “These guys, man they would need lots of SPF, because they're really fair skinned,” and accordingly emerge only at dusk, Franklin said. You can even shine a flashlight right through them (which is technically known as "candling," by the way).

And these things are about as comfortable above ground as we are below it. It’s hard to classify their method of locomotion. The critter isn’t using its limbs much, and it isn’t quite slithering. It’s actually anchoring itself at points along its body, then pushing forward. This makes sense underground: By contracting itself against the walls of its burrow, the Mexican mole lizard can slowly inch forward, leaving its limbs free to shove loose soil back.

Those powerful claws help the creature shovel dirt out of the way. Carl Franklin

Now, a year ago I featured another charming little subterranean creature, the pink fairy armadillo from Argentina. Like the Mexican mole lizard, it faces a problem living underground: thermoregulation. As a burrower, you’re pretty much stuck with the temperature of the soil. You can’t seek shade or water to cool down. The armadillo has solved this problem by turning its shell into a radiator of sorts. If it overheats, it can pump blood into the shell, cooling itself down. Conversely, if it’s too cold, it can pump the blood back into its body to raise its core temperature.

The Mexican mole lizard isn’t blessed with such a shell, so how does it regulate its body temperature? For the moment, Franklin isn’t sure, though he notes that he’ll find them in the roots of vegetation, perhaps taking advantage of the cooler soil under the plant’s shade. “So they would just move from one site to the next for thermoregulatory needs, is my educated guess.”

Mexican mole lizards lack pigment because it wouldn't really do them much good, on account of spending pretty much their entire lives underground. A spray tan wouldn't kill them, though. Just saying. Carl Franklin

Also a bit of a mystery still is their sex life. According to Franklin, “the rules that you would use for sexing lizards and snakes just pretty much go out the window,” which is probably a sentence you never thought you’d ever read. Male snakes and lizards, you see, have sex organs known as hemipenes, two of them to be exact, which they use alternately to fertilize a female. Because of these, typically males will have bulgier or longer tails, but that’s not the case with the Mexican mole lizard, whose hemipenes are particularly tiny.

Accordingly, Franklin isn't sure if he even has both males and females in his lab—somewhat of a necessity if you want to get things to breed. For his sake, I hope he does. The less time snagging more specimens out in the field and making the locals uncomfortable, the better.

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.