go mad
verb
Definitions
To become insane.
(typically followed by "and" and a second verb) To do something extravagant.
Example: Here's fifty pounds in case you see anything nice to buy, but don't go mad.
(usually as a past participle and preceded by a noun) To reach an excessive or ridiculous level.
Example: Why should we ban controversial speakers from college grounds? Surely that's political correctness gone mad?