Scott Pilgrim vs. The World: Unlock Mr. Chau and Mrs. Chau as Strikers
In Scott Pilgrim vs. The World for PS3 and Xbox 360, you can unlock Mr. and Mrs. Chau was summonable strikers.
Randomly on the world map, you’ll see Mr. Chau located on a stage. Go to that stage immediately after you see him and you will be forced to fight him. Defeat him and you’ll unlick him and his wife as strikers.
His appearance can be pretty rare, so it might take you multiple play-throughs before you even see him the first time. Keep your health up, because the last thing you want is to lose the fight and have to wait again.