Our eventual cession of global dominance to giant spiders came one step closer this month when a scientist detailed his encounter with a spider that weighs roughly as much as a puppy. The South American Goliath birdeater (real name!) has a footlong legspan and two-inch fangs. Its body is about the size of a fist and it is the largest spider in the world—that we know of.

Piotr Nasrecki was in the rainforest of Guyana a few years ago when he had a run-in with the “almost mythical” creature. From his blog:

I heard the rustle of an animal running. I could clearly hear its hard feet hitting the ground and dry leaves crumbling under its weight. I pressed the switch and pointed the light at the source of the sound, expecting to see a small mammal, a possum, a rat maybe. And at first this is what I thought I saw – a big, hairy animal, the size of a rodent.

Despite seeming like an eight-legged waking nightmare, Nasrecki says the Goliath birdeater is “pretty much harmless to humans.” But, should you find yourself in the Guyanese rainforest, maybe keep your distance anyway, since its fangs are “capable of puncturing a mouse’s skull.”

Having fun trying to sleep tonight!

[Image via Piotr Nasrecki]