Spiders, to the squeamish, are already pretty gnarly on their own. However, even the toughest tough guy would stop in his tracks upon encountering the goliath birdeater, a tarantula that can grow up to a foot long and weigh as much as a young dog. However, that’s exactly what happened to wildlife photographer Piotr Naskrecki, who snapped pictures of the beast when he encountered it in a rainforest in Guyana.

“When I turned on the light, I couldn’t quite understand what I was seeing,” Naskrecki, an entomologist and photographer at Harvard University’s Museum of Comparative Zoology, told to LiveScience. The birdeater (which typically doesn’t actually eat birds, though it could) is arguably the largest spider in the world, significanyl outweighing the lankier huntsman spider.

The spider is so large that Nasrecki described it as making noise as it walked, similar to a horse’s hooves though not as loud. The spider’s venom doesn’t pose much of a threat to humans, though Nasrecki says that getting bitten with one of its two-inch fangs would be “like driving a nail through your hand.”

In addition to the massive fangs, the spider uses its body hairs as a line of defense. It can use its legs to slough off tiny hairs, which then irritate the eyes and mucous membranes of any would-be attackers. Those hairs also rub together to give off a threatening hissing sound, described as sounding like velcro being pulled apart.

Despite its imposing figure, the spider actually subsists mainly on earthworms, though it has been known to feast on snakes, frogs and even bird eggs. Fortunately your odds of encountering one appear slim: The spider is so rare that even Nasrecki hasn’t seen it much.

“I’ve been working in the tropics in South America for many, many years, and in the last 10 to 15 years, I only ran across the spider three times,” he said.