Mayan Death Whistle
I found this to work best out of several available models on various sites.
Per the original author:
PLEASE DO NOT ASK TO SELL THIS ITEM, I WANT IT TO ALWAYS BE FREE FOR ALL AND NOT TO BE PROFIT FOR ANYONE.
Original description:
Adapted for my custom designed Death Whistle Resonator. Its designed to be very strong, easy to print and very loud.
Worn for ceremonies and taken into battle to intimidate enemies by recreating their death screams as a sign of their impending death. Read more about Death Whistles here http://www.mexicolore.co.uk/aztecs/music/death-whistle
See print instructions for more guidance as needed.
This is reposted from @Tony at Mayan Death Whistle, which was reposted from Tacblades at Maya Death Whistle (Easy Print, Very Loud) both under Attribution-NonCommercial-NoDerivatives 4.0 International which this posting also inherits. That model was remixed from Maya Skull.