Verb
shit a brick (third-person singular simple present shits a brick, present participle shitting a brick, simple past shit a brick or shat a brick or shitted a brick, past participle shit a brick or shitted a brick or shat a brick)
(idiomatic, vulgar) To react strongly or excessively, especially in anger, fear, or astonishment.
If our boss finds out we did this and didn't tell him, he's gonna shit a brick.