Have you ever felt jealousy? Tennisball has. But this jealousy makes TB take it to the extreme. This causes many damages, like death, outbreaks, and many more. Soon, TB will end up alone if he doesn't STOP.
This is in Sophomore year in a humanized AU, the same AU where Foldy and Stapy are together. TB had a crush on GB for a looooong time now and still is convinced that GB only likes him in a platonic way.