Mayhem 3D

You can earn mayhem points in both Career and Exhibition modes. You need 100,000 mayhem points to earn this trophy. Completing and getting all stars in Career mode should be enough to give you 100,000 mayhem points.

In case you need more points, you can grind this in Exhibition mode, Domination event. Select 11 opponents for maximum points - about 6000 in a single event. Repeat the race until you get the amount you need.