Bax Kapoor is a fifth grader in Ms. Starr's Upside-Down Magic class at Dunwiddle Magic School. He is an upside-down Fluxer who turns into a rock. He is one of the focuses of Upside-Down Magic #2, Sticks and Stones.
Bax is a dark, brooding boy who wears pirate, skull-and-crossbones, and shark t-shirts. He likes to wear the sort of clothing that shows he does not want to be messed with.
Bax is an upside-down Fluxer who turns into things. Most of the time he turns into a rock, a large, gray rock. Once he fluxed into a leash in order to save Andres. Once, in the Show-Off, he fluxed into a player piano. Bax cannot turn back on his own. His original potion to flux him back, Burtlebox, was proven to have serious side effects (like turning things to stone), so now he has a new one.
Bax is a reserved, often grumpy boy who wants to be cool. He's upset by his parents' divorce, but he tries to keep that to himself. Despite himself, Bax really respects Ms. Starr and likes his UDM friends. He often thinks that people don't notice him.
Bax's parents divorced before his magic came in. The magic came in randomly; one minute he was eating ice cream, and the next he was in the hospital, having turned into a rock. His dad moved to Dunwiddle to let Bax attend Dunwiddle Magic School; his mother works in Cider Cup, a nearby town. Bax stays at his mom's Saturday and Tuesday nights and his father's the rest of the time.
- Bax is the only UDM kid known to have divorced parents.
- Bax plays piano, making him one of the six musicians in the UDM class.
- The name "Bax" means "baker".