cadere dal pero

Italian

Literally, “to fall from the pear tree.”

(informal) to be very surprised; to be a deer in the headlights
- 2020, Masterchef Italia, season 9, episode 15, spoken by Giada Meloni:
  Mi fa un po' sorridere la reazione di Luciano perché è sempre quell'espressione di chi cade dal pero, e io non ci credo.
  Luciano's reaction is kind of funny to me, because it is always that expression of being a deer in the headlights, and I don't believe it for a second.