go berserk
To go crazy, especially in anger. The phrase, and the word "berserk" itself, is related to a group of Norse warriors called "berserkers," who were known for being violently frenzied in battle. Mom will go berserk if she catches you sneaking out after curfew again.
go berserk
to go crazy. She went berserk and strangled her cat.
go berserk
Erupt in furious rage, become crazily violent. For example, When they announced the gymnast's score, her coach went berserk. This expression is believed to allude to the name of Norse warriors renowned for their ferocity in battle and for wearing no armor but a bearskin shirt (or berserkar). [Late 1800s] Also see go ape.