What's your worst nightmare? Get ready to replace it with this image: a puppy-sized spider with legs the size of a "child's forearm."

The world's largest spider recorded by the Guinness World Records is a Theraphosa blondi, a male goliath bird-eating spider, which was collected in Venezuela in 1965. It had an 11 inch leg span, big enough to cover a dinner plate.

Piotr Naskrecki, an entomologist and photographer at Harvard University's Museum of Comparative Zoology, almost stepped on one just like it, according to Live Science.

Naskrecki was going for a nighttime walk in the rainforest when he thought he heard the underfoot rummaging of a possum or another mammal. 

Oh no. Not a rat.

It was a spider, only this type of spider is so big, it has sounds.

"Its feet have hardened tips and claws that produce a very distinct, clicking sound, not unlike that of a horse's hooves hitting the ground (albeit, admittedly, not as loud)," Naskrecki wrote on his blog. "But this is not the only sound this spider makes."

"Every time I got too close to the birdeater it would do three things," Naskrecki continued. "First, the spider would start rubbing its hind legs against the hairy abdomen. 'Oh, how cute!,' I thought when I first saw this adorable behavior, until a cloud of urticating hair hit my eyeballs, and made me itch and cry for several days."

"If that wasn't enough, the arachnid would rear its front legs and open its enormous fangs, capable of puncturing a mouse's skull, and tried to jab me with the pointy implements," Naskrecki wrote. Birdeater venom is not deadly, but who wants to be punctured by 2-inch fangs?

And don't forget the hissing. The spider produces a warning hiss by rubbing its hook-like leg hair together. Naskrecki claims the spider is harmless to humans... well, unless it bites you. That would be as pleasant as "...driving a nail through your hand," Naskrecki said.

So, this huge spider with 2-inch fangs doesn't actually eat birds, despite it being dubbed as the "bird-eating spider." It may be able to attack small mammals and puncture and drink bird eggs, but the spider's main source of nutrition is the earthworm, according to Live Science.

Naskrecki told Live Science that he has only seen three of these giants in the last 10 or 15 years, so...

Sleep easy tonight.