- Durandal: "Yes, that brownish purple goop is disgusting. Yes, it smells strange. Yes, its a part of the pfhor biology. No, I'm not telling you what it is. I'd never get you to leave your current location if I did. Hold your nose and jump in..."
— From Marathon: Rubicon
- GLaDOS: "Please note that we have added a consequence for failure. Any contact with the chamber floor will result in an unsatisfactory mark on your official testing record. Followed by death. Good luck!"
— In a grimy water room, Portal