Man Walks in South American Rainforest at Night, Sees Spider the Size of a Small Puppy

In a story that will haunt my dreams, entomologist Piotr Naskrecki was walking through the rainforest of Guyana at night in search of katydids, as that is what he was studying. He says that typically in his field research, he walks slowly and quietly, so as not to disturb anything. He wears a headlamp, but turns it off on occasion, which he says helps him zone in on the sounds around him. Naskrecki was listening for the distinctive sounds of katydid wings when instead he heard something moving, crushing dry leaves under its feet. In his peripheral vision, he saw what he thought was a large, hairy rodent.
It wasn't a large, hairy rodent, however. Instead, it was my very worst nightmare: the largest spider in the world. A South American goliath birdeater (Theraphosa blondi), to be exact. This big, hairy bowl of wrong has legs up to a foot in length, with feet that have hard tips and make clicking sounds as they move along. Its huge fangs are capable of puncturing the skull of a rodent with one clutch. Its size was compared to that of a newborn pup.
Naskrecki said that not only did the spider make a hissing sound, rear its front legs and flex its monstrous fangs, but it rubbed its legs against its abdomen, producing a hairy cloud that made Piotr's eyes tear up and burn for several days afterward. (As I've written this and uploaded the images, I've stopped to take deep breaths several times and once glanced at a world map to remind myself how far that species is from me.)
Read more about Naskrecki's close encounter with Satan's housepet here.