What is a good prank to pull?

You could wait until someone goes to the bathroom. Then we that person comes back have everyone talk in an accent. You could also try the buckt of water over the door prank seen in many tv shows and movies e.g Drake and Josh, The Parent Trap, etc. Also another is prank is to lie to someone and then reveal it was all a prank. You could also draw a fake bruise on your body or use stickers to fake a bruise. Then make everyone believe you actually got hurt. But be carefull as you may end up seeing the school nurse or even a doctor. You might even go to the hospital so do this prank it a good time.