Therm

Professor Therm is a performer in Master Payne's Circus of Adventure. She's a bit of a mystery, as unlike the Circus' other named performers, she only shows up once (here), doing a little stage routine with her colleague Professor Moonsock. Master Payne had introduced her in the previous edition as an explorer of the Americas, where she supposedly picked up the towering musical masterpiece that she and Moonsock are performing.

The fact that she's never seen again makes it possible that "Professor Therm" is actually a stage name for some other Circus member that we do see. She bears a slight resemblance to Zeetha, Daughter of Chump, possibly including Zeetha's hair color (which certainly is distinctive). However, Zeetha's hair is so distinctive, and her usual stage gig (martial arts) so prominent as well, that good stagecraft would call for the Therm role to be played by someone less recognizable. Whatever the answer, she's had her moment of fame.