Karma, once again, finds himself forced to school early to set up his next prank. This time, he brings some incredibly large rubber bands along with a suspicious amount of fishing line, on top of a collection of normal and not-normal water balloons color coded to their target.
Gravity has failed me, I will have to find a new way of delivering the payload. I will defy physics and do the impossible if I have to. She may be able to block her head, but she can't block every angle. Kyousuke-kun might have access to whatever camera or other trick she is using to see my pranks coming, but lacks the raw skill. It won't hurt to do the same trick on him. Guide my balloons, Aniki!
Karma then finds several inconspicuous and close-by places to make water-balloon catapults, half aimed at the teacher's desk and the other half aimed at Kyosuke's. Normal balloons for the teacher, red ones for Kyousuke. He had plenty of warning. Karma then attempts to connect them as secretly as possible using the fishing line, in a way that will trigger each set when the target's chair is moved. Each one is held in firing position by something easily removable, such as a pencil or specially bent paper clip, which will hopefully release it when removed.
...At this point, I don't know if this idea is even physically possible. But I control a seamonster, 'physically possible' is a strange word for me to use. So in case this Roadrunner-esque idea fails, I will keep a red balloon on me. He isn't getting out of getting wet that easily...