I hear he's looking for work.

Sounds like my kids' teachers … well, at least the elementary school principal.

This goes along with the current practice of only hiring adjuncts to keep down costs (I tried to post a link but it was taken down - Noam Chomsky wrote about this a month ago. I thought he could guest star and hang out with Lisa).
Or Otto graduates after fifteen years of night school and budget cuts (again) mean he…

He was an adjunct.

Professor Frink!!! He is having trouble getting grants to do his work, so he has to teach Bart's class. He completely confuses them (although somehow Nelson develops an aptitude for physics, which he employs in his bullying techniques). Bart misses Mrs Krabappel while Frink "hoyven-flavens" at the class.