Slime Demo from The QuakeLab by Steve Fukuda is a Single Player level.
Walkthrough
Turn left to look at a pool of Slime.
Gallery
Slime Demo from The QuakeLab by Steve Fukuda
Alternate Versions
Aftershock for Quake version using the Aftershock Level Theme.
Slime Demo from The QuakeLab by Steve Fukuda (Aftershock)