Fry drop

From neurolinguistics. It describes any phrase which can be used to demonstrate how the brain selectively re-interprets nonsensical language when delivered with a false context. The original social experiment involved walking up to a stranger and initiating a conversation. Then once they were on verbal auto-pilot, delivering the statement as the first half of a conjunctive pair along with a misleading cue.

eg;
You: Excuse me, do you know the way to the library?
Stranger: Yes it's just up that street there.
You: Is it far? I have to meet my Sister at two o'clock.
Stranger: Umm, no. About half a mile.
You: (glancing at bare wrist) Arcing jet of semen? It's just I don't have a watch.
Stranger: Yes, it's just after one-thirty.

It's possible to use this technique to drop practically anything into a conversation without it being consciously registered by the other party. The etymology nods to British comedian Stephen Fry who often used it as an inside joke for his friends.