Doodle Pong? OMG!

Don't let the objects ruin your exam! Help Johnny to beat them!

In my science exam, a doodle caught my attention, I tried to erase it, but as I got closer a portal beams me to a world of doodles. Impossible! This can't be real. I must finish the exam or I will repeat the course and there is no way I will do that, a clip appeared at the top of my exam, It hit the pencil and it bounced off, I thought it was finished and I was ready to go for the same portal, but more elements appeared and I realized that the exam would be longer than expected.