Beat the metal head mash, known as Beat the metal head mash game in the PS3 collection, was a mission in Jak II. According to Tess Krew hid something inside the Metal Head Mash game machine, Daxter decided he would show off and attempted to win whatever it was Krew had hidden.
Each of the hole corresponds with a button on your controller and you'll have to use this to hit all the metal head dummies. Gold ones are worth more points than grays, while the red ones harm you. If you miss too many or hit too many reds you'll lose the game and be forced to try again. You need 1500 points to find the hidden prize.