Sketch using a modified Mozzi SampleHuffman class to play an audio sample at the press of the button (when pin D4 is held low.) Audio output as per standard Mozzi conventions, pin D9 on an Arduino.
Audio is the classic stock sound effect known as the Wilhelm scream downloaded from Archive.org and downsampled using Audacity to fit within flash memory of an Arduino
Mozzi library released by Tim Barrass under CC-BY-NC-SA
Wilhelm scream is public domain for most practical purposes
Sketch source code released by Roger Cheng under MIT License