S1, E5: 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. Through this ordeal, he earns the trust of the forest tribe and is given the leads he is looking for. After meeting with a victim attacked by a mystery creature and a hunter who claims to have shot a mapinguari, Spain is introduced to an ornithologist who believes the creature is a relic population of prehistoric giant ground sloths. But it's a distinct animal call in the dark of the Amazon, mimicking the locals' descriptions, that energizes Pat's investigation.