Also known as Hunhau, he was the Mayan god of death who ruled over Mitnal, the land of death, the lowest and most horrible of the nine hells. He was normally represented with the head of an owl on a human body. This figure of death has survived to this day, where the Indians of Central America and Mexico believe that someone will die when the owl screeches. In other representations Ah Puch is shown as a skeleton or a bloated corpse, adorned with bells. He is also referred to as 'God A'.

from: Mayan Mythology