Help! I'm Trapped... (book series)

Jake Sherman is an Ordinary Middle School Student, who is condemned to help his Mr. Dirksen, his grouchy science teacher, finish his experiment as part of a routine detention. However, when lightning strikes the house, Jake gets knocked out, and wakes up in his teacher's body. After that, his middle school life is pretty much doomed to wackiness and hilarity.

Written between 1994 and 2001 by Todd Strasser, this series would have been a very popular series, but was overshadowed by the monumental popularity of series like Animorphs and Goosebumps.

Tropes used in Help! I'm Trapped... (book series) include:

Bluff the Impostor: Jessica (Jake's sister) tries a blending of these tropes on Jake and Mr. Dirksen, to see which is which. Finally, she asks Jake a trick question to see if it's really him, and he answers it correctly.
Freaky Friday Flip: All but two of the books. Usually it's Jake, but occasionally his friends Andy and Josh get in on the action.
- Jake himself ends up in the bodies of Mr. Dirksen (his science teacher), the President, his sister, a dog, his uber-muscled gym teacher, a movie star, an alien, Santa Claus...
Fridge Logic: A case happens to Jake. When he gets stuck in his dog's body, he dreads eating dog food, mainly because he thinks the food contains chicken lips. As he's about to be discovered by his sister, he quickly thinks "Do chickens even have lips?"
Groundhog Day Loop: If it's not a Freaky Friday Flip, it's this. Only happened twice though; once in the first day of school, and in the first day of summer camp.
- In the first one, it introduces some very important recurring characters, and a massive amounts of Character Development. The second one, he helps the Butt Monkey gain confidence to stand up to a bunch of bullies, some character development that has already happened a few times, and finally remembers to brush his teeth after many repetitions.
Heroic BSOD: In Help! I'm Trapped in the First Day Of Summer Camp, Jake suffers a mild case of this partway through the book. Without breaking away from his BSOD, he demands to be taken away from the camp (his parents would get the refund), and threatens his sister (she ate his doughnuts). All Played for Laughs.
Mundane Utility: The body-swapping machine has enormous implications on the nature of intelligence, psychology, and the soul. Jake and his friends use it to spend a day as a celebrity, to keep Jake's dog out of obedience school, and to get the local bully expelled.
Protagonist-Centered Morality: Jake swings back and forth between a great guy, a Jerk with a Heart of Gold, and a straight-out Jerkass.
Shipper on Deck: In the first book, Jake actively ships for Mr. Dirksen and the hot teacher, Ms. Rogers.
Something They Would Never Say: See Bluff the Impostor, above.
Spot the Impostor: See Bluff the Impostor, above.
Tag-Along Actor: In Help! I'm Trapped in a Movie Star's Body, the eponymous movie star tags along after the Ordinary High School Student protagonist.
Who's on First?: In one book, Josh tries to get the local bully, Barry Dunn, expelled when he's in the principal's body. After their plans fail, the bully starts to gloat, and Josh interrupts "Are you done?" The bully responds with "Of course I'm Dunn," and continues to gloat. This happens two or three times before Dunn starts insulting Josh's intelligence. And Josh expelled him.