From my mom, not my grandparents, but we’ve gotten a lot of mileage out of this one

“If I find it, can I hit you with it?”

Used when we were bugging her about not being able to find something. Don’t believe she ever made good on that threat, but it usually did it’s intended purpose of getting us to quit bugging her and find it ourselves. And if it was something we really needed help finding it would have been an acceptable trade-off.

My sister got a lot of use out of it with her college roommates and my wife and I use it with each other pretty regularly.