What is this trope called, if it even has a name?

When a professor is teaching some esoteric but vaguely related to the plot subject and an old friend sneaks into the class and stands/sits at the back, and then as class ends, the old friend tells the professor that he needs his help to save the world/embark on a quest?I’m thinking specifically of Indiana Jones and maybe Inception, but I feel like I’ve seen this in a lot of 90’s B-horror/sci-fi movies. My friend thinks I’m crazy that this is a thing and I’m trying to prove her wrong so any leads would help - unfortunately TVTropes.com is turning up nothing.Edit: thanks u/MrPhillly - it is called the Poopy Professor. Submitting now to TV Tropes via /r/movies https://ift.tt/2JpqWrN