From Creatures Wikia
There is a hidden surprise in the doos.wav file, otherwise known as the sound a doozer makes while it's teaching words to creatures. If you open the .wav file (found in the Creatures 2 > Sounds folder) in a sound editing program, reverse it, and slow it down, you'll hear a crowd of Cyberlife/Creature Labs employees chanting "Hell no, we won't go!".
This is supposed to show the doozers' reluctance to leave Albia, originally being a chant opposing the forced draft of the Vietnam War. Another case of Albia mirroring Earth?
If you're lazy you can download the edited sound (OGG format).