flip out
phrasal verb.to suddenly become very angry, excited, or scared and lose control of your emotions.
phrasal verb.to react with sudden, intense emotion or irrational behavior; typically functions as an intransitive phrasal verb indicating a loss of composure.
“My mom will flip out if she sees this mess.”
“He completely flipped out when he realized he had lost his passport just hours before the flight.”
“The crowd flipped out as the lead singer unexpectedly jumped into the front row during the final chorus of the set.”
usually used without an object to describe a person's sudden emotional reaction.
contrast with 'freak out' (very similar) and 'lose it'; 'flip out' often implies a more explosive or visible reaction than just being worried.
when directed at a person, the preposition 'at' is required because the verb is intransitive in this sense.