I wasn't happy with some of the other death whistles designs out there, so I combined the existing base whistle, with a skull from Tinkercad, and the results look pretty good!

The thicker2 version is even more modified with thicker & easier to print areas, where I found the print typically fails for me. I recommend using this version.

With the thicker2 version, I've been able to print tons of these at once, that all work, to give out on Halloween! ;)