You were playing basketball with your team and a rival team. It wasn't a serious match or anything, just for fun. Both teams were playing seriously, though.

Nobody was really passing the ball to you. You were basically just following where the ball goes and running. Soon, you just stood still for a little when nobody was passing the ball to you.

You zoned out after just standing for a bit. The ball was suddenly passed to you and you didn't have time to react before it hit your head. And the ball was hard..