Ah Puch (Hun Ahau, Cum Hau, Hunhau, Hunahau, Yum Cimil, 'Lord of Death') was the Mayan god of death, disaster, and destruction. Ah Puch ruled Mitnal, the lowest level of the Mayan underworld. The Mayans believed that Ah Puch stalked them like a hunter stalks his prey. You can't worship Ah Puch so much as try to keep him at a great distance, so to hedge your bets you should mourn with loud wailing in order to scare him away and prevent him from taking anyone else to Mitnal.
Read Article: Ah Puch, God of Death in Mayan Religion, Mythology