Deep in the jungles of South America, a group of Indigenous people known as the Shuar have a perplexing tradition—shrinking the heads of their enemies. This practice dates back to ancient times, becoming widespread in South America over 3,000 years ago. The Shuar believe that the human head contains a soul, and by shrinking the head, they can imprison the enemy's soul to prevent revenge. After a victory, the Shuar perform a series of mysterious rituals, including feasting and dancing, to ensure that the soul cannot escape. The shrunken heads are sewn shut at the eyes and mouth, wrapped in cloth, and buried in a pot beneath the hut of the victorious warrior.

The Shuar faced the equally fierce Inca army. Around 1450 BC, the Inca forces, led by Yupanqui, attacked a province in the southern kingdom of Quito. Despite the well-trained Inca soldiers, the Shuar's head-shrinking technique instilled fear in them. During battles, the Shuar would decapitate their enemies, and after several days of ritual processing, shrink the heads to the size of a fist, effectively imprisoning the enemy's soul. This process is filled with mystery and horror, making it hard to believe.