For those who want to celebrate Halloween like it’s 1399: Scientists are sending shivers down the internet’s collective spine by recreating an ancient “Aztec Death Whistle” that’s said to emit the “most terrifying sound in the world.”

The macabre kazoo is detailed in a new video produced by the Action Lab, a group of proud internet nerds who specialize in mind-bending experiments.

“The sound that the death whistle makes innately strikes fear into your heart,” intones presenter James J. Orgill in the clip while holding a 3D-printed version of the instrument.

The Brigham Young University engineering grad then plays an audio clip of the scream machine, which evokes a bloodcurdling, bansheelike shriek resembling a sound effect from a haunted house attraction. (We dare you not to jump!)

Orgill points out that this is not a “human scream” but rather the sound emitted by the replica of a skull-shaped artifact originally discovered in Mexico City in 1999 by archaeologists.

It was reportedly found clutched in the hand of a headless skeleton in a temple dedicated to the wind god Ehecatl — one of many sites where the Aztecs conducted human sacrifices.