OUTRAGEOUS TROMBONE BELL
This is nothing but the bell section of a discarded brass instrument fed by air blown through a latex balloon neck. When you constrict the air flow through the neck by stretching and flexing in various ways, you can get lots of extreme sounds, and the acoustic efficiency of the expanding bell in sending these sounds out into the surrounding air is astounding. The balloon neck has a short section of plastic pipe at the end to make it easier to hold in the mouth and blow.
In the sound clip, sound samples from the trombone bell were recorded, digitally pitch-shifted, and edited together.