KNOCK YOUR SOCKS OFF

Meaning: If some fact knocks your socks off, it means it surprises you a lot.

For example:

Donna and Antonio knocked everyone’s socks off when our mafia Family had a karaoke night. They did the best singing we all have ever heard before in karaoke.
At the last Mafia meeting Corleone ordered himself for the 1st night and revealed as a false Sheriff afterwards. Corleone knocked Tano’s socks off by doing that, because Tano was a real Sheriff and he was executed by citizens right away.

You can practice this idiom soon at one of the English Mafia Club’s upcoming meetings: https://englishmafiaclub.com/events/upcoming-events