Harvard entomologist and experienced field scientist Piotr Naskrecki has over 30 scientific papers with his name on them. But being knowledgeable and prolific doesn't immune one from being startled by a giant spider while taking a stroll in the rainforest.

That's what happened to Naskrecki in Guyana, the small South American nation just north of Brazil. As Naskrecki relayed on his blog, he was taking a stroll when he heard the rustle of a small animal. Shining his flashlight at the source of the sound, he expected to find a rat or a possum. Instead, he came face to face with the largest spider in the world -- the South American Goliath birdeater (Theraphosa blondi).

Most people, when confronted with an enormous arachnid in the midst of a dark forest, turn and run the opposite direction. Not Naskrecki. "I was lunging at the animal, ecstatic about finally seeing one of these wonderful, almost mythical creatures in person," he recalled.

The Goliath birdeater is most certainly huge, but though it could potentially take down a small bird, Naskrecki said they're unlike to find such a meal scavenging the rainforest floor in the middle of the night. Instead, the spider -- which can grow up to a foot in length and boasts one-inch-long fangs -- feasts of earthworms -- lots and lots of earthworms. It's one of the few spiders that makes noise as it walks.

As frightening as it is to most normal people, the birdeater isn't poisonous. However, its bite is said to feel similar to a wasp sting, and can leave holes in the skin where its fangs enter. It also uses a defense mechanism whereby it releases lots of tiny barbed hairs by rubbing its hind legs against its abdomen.

"The urticating hairs ended up in my eyes and mucus membranes -- now I know better than to put my face too close to these animals," Naskrecki said, remembering that he itched his eyes for several days after the encounter.

Naskrecki has seen the massive birdeater three times in his 15 years traveling to South America, and each time he still gets giddy with excitement. Thanks to him, less adventuresome spider lovers can appreciate the birdeater through the computer screen.