Golden Apples can be earning by completing the mini games in the unstable amount based on score earned per game. Golden Apples can be used by many periodical events. The golden Apples will be spent by buying exclusive items in the event or spending for combating with event's characters. Golden Apples also could be obtained by spending IAP too.
Tournament and Golden Apples

Tournament with Golden Apples.

Golden Apples can be earned in Mini Games! Spend Golden Apples to compete in the Tournament! Spend Golden Apples to play a Daily Challenge (Challenge mode only)