The Mongolian death worm is rumored to live in the Gobi Desert, one of the most inhospitable regions of the planet. This freakish creature is said to spray acid, send out electric shocks and explode when threatened. After traveling to the vast, empty wilderness, Spain dives in with the locals to garner some leads. To impress them, he finds himself in over his head- literally - fighting one of Mongolia's top wrestlers.

For generations, fishermen have told tales of sea monsters. One of the world's most legendary monsters is a sea serpent known as Cadborosaurus, or "Caddy," which has been reported off the coast of British Columbia for more than a century. But to science, it doesn't officially exist. Now Pat travels to Vancouver Island to track it down. He questions eyewitnesses, explores the myths of the coastal people who have occupied the area for more than 5,000 years and confers with top oceanographers.

Ever since the earliest missionaries and explorers returned from Africa, stories have been told of strange water-dwelling monsters living in the Congo Basin. The native Pygmy tribes speak of the Mokele-mbembe, an animal with a long, thin neck and a body the size of an elephant that seems to resemble a sauropod dinosaur. Could there be a population of dinosaurs living in the remote jungle?

Deep in the Brazilian Amazon lurk tales of a massive one-eyed monster. With slashing claws, savage howl, noxious stench and a gaping mouth in its body, the locals tremble to repeat its name: mapinguari. To gather concrete information on the creature, Spain must gain the confidence of the local tribes. He takes part in an extreme initiation ritual: wearing gloves lined with venomous bullet ants. The insects' stings send Pat into a hallucinatory world of pain.

In the vast jungles of mystical Sumatra, locals have reported seeing a creature that looks something like an ape, yet it walks just like us. They've named it "Orang Pendek" - the little man of the forest. A recent scientific discovery proposes that another species of humans - nicknamed 'hobbits' - did once live in Indonesia. So could there be a new great ape waiting to be discovered? Or is it possible we're not the only human species living on earth? Biologist and beast hunter Pat Spain investigates.