degenerate into (something)
To get worse and enter an unpleasant state. Concerts always seem to degenerate into chaos once it's time to leave the venue. If you don't exercise regularly, your muscles will degenerate into mush.
degenerate into something
to decay into something; to break down into something. The peace rally degenerated into a riot. I was afraid that the party would degenerate into a drinking contest.