Donnie's science teacher is named Professor Monnitoff. The title of professor means Monnitoff spent multiple excruciating years in school. Most grad students go through this hell so they can work at an esteemed college. Prof Grand Moff, which is what he should ask students to call him, is seriously slumming it by teaching in a high school, especially at a private religious high school. Religious schools don't have the best reputation for their science curriculums.
Professor Monnitoff and Donnie discuss time travel, as one does with one's overqualified high school science professor. Time is pre-determined by God, explains Professor Monnitoff, a man with a PhD IN SCIENCE. Donnie then says that he could alter time if he traveled in "God's channel" because I guess God has the carpool lane equivalent of time travel. Instead of shaking his head and chuckling in response to this sixteen year old's thoughts on cruising through time using the Lord's interdimensional shortcuts because WHAT, Professor Monnitoff tells Donnie that their conversation could get him fired.
I do think that if another adult overheard their serious conversation about the best way to TRAVEL THROUGH TIME, they would definitely fire Professor Monnitoff, but not for the reason he thinks.
Donnie's friends are hanging out and discussing how badly they want to bone the cartoon character Smurfette when Donnie ruins their fun by interrupting to explain Smurfette's true origins and sexuality. His knowledge of the Smurfs obliterates his friends' minds, and they announce that Donnie is a mental giant.
If knowing trivia about 80s kids shows qualifies you as a genius, then why hasn't Mensa called me yet?