On the night of Friday, June 13, Thomas Gullett, a butler, was out gathering flowers on Robert Allerton’s large estate just west of Monticello, when something emerged from the shrubbery and attacked him. The beast, Gullett later claimed, was an African lion: It pounced on the butler, toppling him to the ground, and the two grappled for a few moments before he seized it by the throat. Apparently bested, the cat broke free and escaped into the hunting grounds of Allerton’s estate, leaving Gullett shaken and bruised but miraculously alive.

What was clear was that not a single person doubted that what attacked Thomas Gullett was an African lion. The question was: What was it doing in rural Illinois?

The world is full of cryptid sightings—strange creatures that may or may not actually exist, that may or may not have been sighted, that may or may not be hoaxes. But mixed in amongst this menagerie of fantastical, improbable beasts, one sometimes comes across depictions of what are known as Phantom Felines or Alien Big Cats (ABCs, for short). These sightings are not of new, hitherto unknown creatures, so much as known animals spotted far outside of their normal habitat.

DO SUCH MONSTERS, WHATEVER THEY are, qualify as “cryptids,” in the same league as Bigfoot and the Loch Ness Monster? Or are they something else? When Bernard Heuvelmans, the Belgian-French biologist, first proposed his definition for a cryptid in 1983, he argued that to qualify, an animal must be “truly singular, unexpected, paradoxical, striking, emotionally upsetting, and thus capable of mythification,” a definition that has more or less been adopted among contemporary cryptozoologists. In other words, an as-yet-undiscovered species of reptile or insect or fish cannot, by itself, count as a cryptid by Heuvelmans’s definition. The thing must, on some level, inspire awe and wonder.