While you are not in a game, one dribble one of the basketballs and win. Now you have the basketball. Do not talk to anyone or enter another area. Face the sticker king, and do a throwing motion. You will throw the ball. If it hits the sticker king, he will move backwards! (If you throw the ball on someone else., that person will not move backwards.)
The Sticker King is the hardest boss in the game. To face him, you must defeat ALL DARE and ALL GAME!
After you beat him, you unlock him in multi player