break bad

verb2

1. •
   (informal) To go bad; to turn toward immorality or crime.

   • Nah, come on, man! Some straight like you, giant stick up his ass, all of a sudden at age, what, sixty, he's just gonna break bad? — 2008
2. •
   (informal) To go wrong; to go downhill.

   • Half the bad men are only coltish cowpunchers gone wrong through rotten whiskey and luck breaking bad for them. — 1913