Slime (Q2)

"All over Stroggos are pools of toxic waste from their refineries. This slime eats away at your flesh unless protected by an enviro-suit."

- The Quake II Manual

Slime is a common fluid found on Stroggos. It slowly drains the player's health, with armor offering little protection, however; Invulnerability and Enviro-Suit are the only powerups that will protect the player from slime. However, similar to Waters, secrets could occasionally hide behind or inside these light-level pools of toxic death, so make sure you have an Invulnerability and Eniro-Suit before jumping in.

Slime is also fairly deadly to enemies as well, although the game commonly offers you a chance to give them a green poison bone and flesh eating bath.

Fortunately, no liquids, including slime, return in Quake 4, most likely due to the id Tech 4 engine's limitations.