Aztec 'death whistles,' used to prepare sacrifice victims to descend to the underworld, scramble your brain, scans reveal

Clay pipe shaped like a skull against a black background.

Ritual Aztec whistles produced a brain-scrambling "scream," according to a new study. The objects were used during human sacrifices and may have prepared victims for their supposed descent to Mictlan, the Aztec underworld.

The Aztecs created the small 1.2 to 2-inch-long (3 to 5 centimeters) skull-shaped whistles out of clay, possibly to represent Mictlantecuhtli, the Aztec lord of the underworld.