This is ‘the most terrifying sound in the world’ — hear the Aztec Death Whistle

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.

Initially thinking it was a toy, per Orgill, scientists didn’t blow into it until 15 years later, whereupon it emitted a terrifying sound.

“‘It was a startling discovery because it sounded like a screaming human,” said the burgeoning YouTube star, who dubbed it the “most terrifying sound in the world.”

The Aztecs were able to create this nightmarish noise by modeling the death whistle after the human larynx.

When the user blows into the instrument, the wind divides in two, producing oscillating sound waves that bounce around a large chamber before leaving via a second hole.

While the purpose of the instrument remains unclear, experts have several theories, with some believing this fright flute was used to scare enemies in battle.

Others postulate that the whistle was a defense talisman used to ward off evil spirits during a sacrificial victim’s journey to the afterlife.

In order to resurrect this symphony of screams for our listening “pleasure,” Orgill blew into different Tim Burton-esque whistles that were 3D-printed by US tech firm HeyGears.

All told, they made the raptor larynx from “Jurassic Park” sound like a kazoo.

No 3D printer, no problem: Interested parties can buy their death whistles on Amazon, which offers duplicates made of materials ranging from resin to carbon fiber.

Many advertise how closely their decibels match that of the most bone-chilling human screams.