You fill your mouth with water and swish it around in your mouth, a trickle starts to dribble down your chin. You're feeling dizzy, you brace yourself against the wall. The chemical seems to be working faster, and you seem to be having an allergic reaction.
Your skin itches all over and looks flushed. By the time you make it back into the locker room and head for the john, you're limbs feel like rubber.
You drop to your knees and vomit, and vomit, and vomit. You feel like you're coughing up all your insides. It seems like 10 minutes, maybe fifteen. You blink away the stars from your eyes, and use the stall to pull yourself up. Your skin is now dark orange and covered with bumps. It looks more reptilian than human. You figure you need to get to the nurse's office, but you trip as your shorts and jock drop down to your ankles. You head for the door. Where is everybody? You look in the full length mirror next to the door where you normally check your fly before exiting, now you see yourself reflected. It's not possible? You'd been carrying your tee-shirt, and didn't realize that you'd lost height as well as mass. Your skin is hot to the touch. Suddenly, there's a loud hissing sound, steam rushes out of your pores as you shrink into a sphere. Good grief!
You bounce in front of the mirror. You are a basketball!
The door opens and the assistant coach enters and scoops you up under his arm. He looks around, and mutters that he thought he saw you come into the locker room, but he must have been mistaken. He marks you absent on his clipboard and returns to the gym. He tosses you Dave the guard and announces it's dribble practice.
After the thousandth bounce, you find you're getting used to your new form, and it suddenly strikes you that the basketball really is the star of a basketball game. You can change players, but you can't play without the basketball.