"Good news. I've just worked out what that thing you just incinerated did. It was a Morality Core they installed after I flooded the Enrichment Center with a deadly neurotoxin to make me stop flooding the Enrichment Center with a deadly neurotoxin. So get comfortable, while I warm up the neurotoxin emitters."
— GLaDOS, Portal
"Warning: Neurotoxin pressure is reaching dangerously unlethal levels."
— Announcer, Portal 2
It's your old friend, deadly neurotoxin. If I were you, I'd take a deep breath. And hold it.
— GLaDOS, Portal 2
The gas we kill with is clear, odorless, totally imperceptible. But that wasn't good enough: I thought people should see it coming, see it creeping up around their legs, through their fingers, inching towards their nose. So my gas is green, the color of life. That's what I like about life. First it giveth, then it taketh away