Hag moth larva
Bugs are some of the weirdest creatures on the planet. Some look cute when they’re fully grown (bumblebees, butterflies, ladybugs), but they all look like Satan’s spawn when they’re in their larva phase. If we came across this thing on a lawn chair, we’d burn the chair with several canisters of gas.
When posted on Reddit, someone helpfully explained that it was a hag moth larva, a.k.a. monkey slugs. They don’t mean any harm despite their intimidating appearances. Hag moth larvae just want to get by, eat a few leaves, and spin a cocoon. They’re free to do so, just not anywhere near us.