If/when it comes to the crunch informal clause
If/when a situation gets critical or you must make an important decision
If it comes to the crunch, he will appear to solve the problem.
He always says he'll help me, but when it comes to the crunch, I can't find him anywhere.
Unfortunately, the computer stops working when it comes to the crunch.
If you say that someone or something is too hot to handle, you mean that they are too difficult or dangerous to cope with.
More harsh or critical than is fair or warranted; unreasonable.