pigs can fly(There is no chance of that ever happening. (Used to show skepticism or cynicism over someone's hypothetical remark.) • Bob: "If we could just get Democrats and Republicans to agree on a tax reform bill, we could bring the deficit down in no time." Dave: "Yeah, and pigs can fly!"kirobite); when pigs fly(or "when pigs begin to fly"); tomorrow never comes(makhno)
be a cold day in hell when(- It’ll be a cold day in hell when I let you borrow my car again!
- Скорее небо упадёт на землю, чем я одолжу тебе мою машину ещё раз!CRINKUM-CRANKUM)