My Best Friend Is Invisible

 My Best Friend Is Invisible was the fifty-seventh book in the Goosebumps book series. It was preceded by The Curse of Camp Cold Lake and followed by Deep Trouble II.

Plot
Hero Sammy Jacobs has two scientist parents and a scientist-in-training younger brother, Simon. Sammy is the black sheep of the family because he doesn't care about science, he cares about science fiction. He busies himself reading books about ghosts and aliens while his brother, is fast at work measuring the growth of his body every day. Sammy’s friend Roxanne comes over to berate Sammy for being such a poor athlete. Sammy lost a track meet earlier in the day and Roxanne wants to make sure he does a better job at the mini-Olympics later in the week. Sammy says he merely let her win and assures Roxanne that he will run faster.

Roxanne and Sammy then get to work brainstorming about their English term project. Sammy suggests studying the life cycle of a moth or charting the growth of plants. Roxanne wants to film a haunted house over the weekend.

Their wild speculation is interrupted by a mysterious light that appears in Sammy's room. The source of this light is revealed to be a special magic flashlight belonging to Sammy's father that allows invisible organisms to be made visible. This light scared Sammy and Roxanne. Roxanne resumes trying to sell Sammy on the haunted house idea. The haunted house is called the Hedge House, because there are hedges in front of the house. Instead of visiting a haunted house, Sammy would much rather spend his Saturday watching the new horror movie School Spirit. His father overhears and confuses this with his son actually having school spirit.

After Roxanne leaves, Sammy becomes convinced that someone's messing with him, as his window is open and his papers scattered around the room. He's sure that a ghost is responsible. The next morning he discovers that Brutus, his cat, opted not to sleep in his room as per usual. He sits down for a nice bowl of cereal, only to discover that while his head was turned away from the bowl, the ghost has eaten all of his cereal.

At school, Sammy is called to the front of the class to solve a math problem. The polynomial equation takes a turn though as an invisible clammy hand grasps Sammy's and he runs from the room in hysterics.

Back at home, Sammy witnesses the scene depicted on the cover of the book. Sammy's mother scolds him for eating the pizza. She then tells him to clean up his room. When he heads upstairs to do as instructed, he discovers that someone has strewn cereal and lunchmeat and other foodstuffs all over his floor. He comes to the conclusion that only a ghost could have caused this food fight. Then the ghost speaks up and confirms this.

Except the voice is not a ghost at all, but an invisible boy named Brent Green. He's twelve too and wants very badly to be Sammy's friend. He explains that he doesn't know how he got to Sammy's house or who his parents are, but he's hungry and wants to be Sammy's friend. Sammy tries to get his family to come see his invisible friend, but they don’t believe him. Roxanne doesn’t even believe him, though she does tell the entire student body about it so they can mock him properly at school the next day.

Things get so bad for Sammy that he has to eat lunch alone in the library. Brent followed him to school and starts eating his sandwich. Sammy begs him to go away, but Brent insists that he's just trying to be his friend. Brent proves his friendship by ruining Sammy's turn in the relay race, costing his team the game.

To make up losing the race to Roxanne, Sammy is forced to agree to accompany her to the haunted house that weekend. Beforehand though, Sammy tries to convince Brent to leave. He tries to get him to live with Roxanne, because she has better food but Brent doesn't want to be friends with a girl.

Brent sees that Sammy's trying to get rid of him and attempts to throw him out the window. He stops himself, before he actually murders Sammy though and explains that he was just goofing around in a familial way. Brent finally leaves after Sammy turns up the radiator high enough to produce steam in his room.

Roxanne and Sammy are at the Hedge House and a ghost does show up. Upstairs in the spooky house, the ghost angrily picks up Roxanne and starts throwing her around the room. Then the ghost picks up a pillow and tries to smother her. Roxanne and Sammy flee from the house. Back at home, Brent reveals that he was behind the whole charade.

Sammy's parents announce that his erratic behavior has caused them to set up an appointment with a mental institution for their son. Before he can be taken away though, Sammy breaks free and runs down to his parents' basement to grab the magic flashlight. He forces the rest of the family and Roxanne to follow him to his room, where he shines the light on Brent, revealing a hideous monster. Brent reveals that his mother made him invisible, so it would be easier for him to make friends.

Sammy and his family can't figure out how Brent can survive with only one head, two eyes, and two short arms that aren't even long enough to wrap around his body. They can't stop being disgusted at how he has hair on top of his head, instead of suction-cupped tentacles. Sammy's father explains that this creature is a human and its their duty to call the zoo, as humans are an endangered species.

Television Adaptation
The surprise ending in the television series episode is mostly different than the one in the book. Sammy's father's flashlight reveals Brent, whose arms are long enough to wrap around his body. Then Sammy's family reveals that they have eyes and mouths in the backs of their heads. After they say that they won't hurt Brent, they gang up on him. It is unknown if they took him to the zoo, since it isn't mentioned in the episode.

Television Episode Trivia

 * This is the only Season 3 episode that originally aired with the Season 2 theme. Later, when the episode ran in syndication, the theme was corrected.
 * This television episode was released on DVD along with, An Old Story.
 * Brent does not mention why he does not make himself known to Roxanne; nor does Sammy offer Brent to be friends with Roxanne instead.
 * The television episode mentions that humans should have all been captured by aliens like that are like Sammy.
 * The media playing on the television when Sam wakes is none other than the Goosebumps television episode, The Scarecrow Walks at Midnight.