Scientist Piotr Naskrecki was deep in a rainforest when he heard rustling from the undergrowth - it turned out to be the world's biggest spider
These terrifying pictures show a spider which is the size of a small dog complete with two-inch fangs.
Scientist Piotr Naskrecki was in a South American rainforest when he heard a noise from the undergrowth.
Expecting it to be a rat, he was left astonished when he saw this monster.
It turned out to be the South American Goliath Birdeater - the largest spider in the world.
Incredibly, the spider has a leg span which can grow up to a foot - which is the size of a child's forearm.
They can also weight more than 6 ounces and come complete with two-inch fangs full of venom.
Speaking to Live Science, Mr Naskrecki said: “When I turned on the light, I couldn’t quite understand what I was seeing."
Later writing in his blog, he added: "Its feet have hardened tips and claws that produce a very distinct, clicking sound, not unlike that of a horse’s hoofs hitting the ground."
The Goliath birdeater belongs to the tarantula family.
Its venomous fangs can break the human skin but it is similar to a wasp sting.
Despite its name, the spider does not normally eat birds. Instead, it usually feasts on rodents, frogs and toads, lizards, and snakes.
