To get out of control with anger, rage, or frustration.
To go berserk.
This is a British expression that was in use before World War II. Probably from spare meaning "excess."
We all thought that Wendy would go spare when she found out that Maurice had spent their rent money buying video games. We were not disappointed.
Malcolm went spare when the liberals passed a law that would lay him off for three months to protect the local prairie dogs.