Behold, the mottled brown, menacing monkey slug. During the fall months, this carpeted creature writhes, wriggles, and inches across apple trees, birches, chestnut, hickories, oaks, and… mailboxes.

In the clip above, a monkey slug, species Phobetron pithecium, is captured in action. Set to dramatic horror music, its body slowly shimmies across the grey metal ridges of a mailbox like a little ball of beige fluff.

The monkey slug is a species of legless caterpillar, but you would not want this larva to crawl across your fingers: the thick fuzz covering the sharp angled spines contain stinging hairs. While some people have willingly touched the monkey slug to see how painful its sting is, you probably shouldn’t pick one up, especially if you have sensitive skin.

Found from New England to Mississippi and Arkansas, these critters can grow to an inch long, shedding their carpet skin as their bodies enlarge. It’s hard to imagine now, but eventually this slug will become an ochre-winged hag moth (although the dark black body and veined wings may still give you the chills).

Beneath all the fuzz and vicious-looking spines is something that appears much more alien. At the 1:13-minute mark, the videographer bravely flips over the monkey slug, revealing the undulating tentacles of its yellow, translucent legless body.

Perhaps the only animal courageous enough to challenge a monkey slug is another monkey slug. Watch this face-off posted by The Caterpillar Lab:

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