I Live in Your Basement!

'''I Live In Your Basement! '''was the sixty-first book in the Goosebumps book series. It was preceded by Werewolf Skin and followed by Monster Blood IV.

Plot
Marco's mother is incredibly overprotective and warns him against all sorts of silly things, like not letting a dog lick your face, or not to run in the house. One afternoon, Marco's school lets out early and he sneaks off to go play softball without telling his mother, who would not approve of such a thing since it is not safe.

As Marco gets ready to play ball with a group of children, including his best friend Jeremy. Gwynnie, a tall athletic girl hits Marco hard in the head with a bat. When Marco wakes up he is laying on his couch while his mother asks him if he is alright. She then proceeds to scold him for playing a dangerous sport and tells him the doctor said he'll recover with a few days of rest. She then leaves the room and a telephone nearby begins to ring. Marco answers it and a boy's voice on the other end tells him that he's glad that he is alright. The reason he states, "You're going to take care of me."

Marco asks who he is and the boy tells him his name is Keith and he lives in the basement. Marco tries to tell his mother about the spooky telephone call. But she informs him that he couldn't have received a telephone call, because there's no telephone in the living room.

The next morning, Jeremy stops by to visit Marco, who is under strict orders not to leave the house. Jeremy and Marco entertain themselves, by playing pool in the basement. Marco is worried that the mysterious "Keith" might be hiding there and the boys go on to discover a squirrel that they confuse for the mystery boy.

That night, Marco can't sleep, so he goes downstairs to fix a midnight snack. He sees the basement door is open and hears footsteps from within. He calls out to see who is there and Keith calls back, reminding him that he lives in Marco's basement. Marco's mother comes downstairs to use the laundry room. When Marco tries to tell her about Keith, Keith yells from the basement for Marco to "Listen to his mother."

The following Monday, Marco's mother lets him go back to school. Marco's teacher forces him to stand in front of the class and talk about having to go to the hospital, but Marco can't remember anything about going to the hospital. After class, Gwynnie chases after Marco with a bat and he scampers away from her.

Once at home, he walks upstairs and is greeted by a young boy with black hair and sunken eyes sitting on his bed. It's Keith! Marco panics and locks Keith in his room, running down to get his mother. But when he brings her back, he discovers he only succeeded in locking in the family dog! Marco's mother is worried and decides to take him to the pediatrician, Dr. Bailey. The doctor informs Marco, after listening to his story, that he is going to need his brain removed. He explains that it's an easy procedure, they just crack open his skull and the brain slides right out. Marco's mother agrees with him but Marco manages to convince them to give him time to get better. As it hasn't even been that long since his injury anyway.

Back at home, Marco attempts to work on a creative writing assignment. But suddenly the screen turns off his word processor and only shows a large picture of Keith's face. Then Marco is choked by Gwynnie, who is in his room. Gwynnie tells Marco that she stopped by to apologize for hitting him in the head with a bat, and that earlier she was chasing after him to apologize.

Marco tries to show Gwynnie the computer with Keith's face on it, but it turns out the computer was not even on. Marco convinces Gwynnie to go down with him into the basement to see if they can find Keith. She does, but they can't find Keith. Then Gwynnie stands at the top of the basement stairs and pulls her entire body inside out through her mouth, the lungs and heart passing past her teeth!

Marco screams so hard that he wakes up in the hospital. Marco's mother is there, and so is Gwynnie. Marco screams for his mother to remove Gwynnie, but she won't because Gwynnie is Marco's sister. Marco realizes that he had dreamed she wasn't his sister and that it was Jeremy who had hit him with the bat. They leave him to rest in the hospital room, and finally Dr. Bailey enters when Marco is by himself. Except that Dr. Bailey now has wavy blonde hair and a tan. He starts to examine Marco, and then begins pulling on his tongue, stretching Marco's tongue out like taffy while Marco screams and screams.

Then Marco wakes up again. Dr. Bailey, this time he is a seven-foot tall man, asks him if he is feeling any better. He then delivers a handwritten note to Marco. The note is from Keith, telling Marco to hurry up and feel better so he can rush home and start taking care of him in the basement. Marco tries to tell his family about the letter from Keith, but Dr Bailey doesn't seem to know what Marco is talking about. When Marco goes to grab the letter, it has disappeared.

The next morning, Marco is allowed to go home and his mother lets he and Jeremy watch a movie and eat homemade pizza. After the movie is over, Marco tells Jeremy he is tired and goes upstairs. In his room, he runs into Keith. Keith tells him that he is real and he is waiting for Marco to take care of him, to take care of everything he needs. Marco panics and hits Keith in the head with a stone owl. Keith drops to the floor and melts into a gelatinous substance not unlike that pictured on the cover of the book.

The gelatinous creature surrounds Marco, enveloping him. Marco struggles with it all the way downstairs, where he slams it against a cabinet, breaking it in two. The two pieces form two monsters and both attack Marco on either side. Marco rolls around on the ground screaming until his mother asks what he is doing. There are no gelatinous creatures on Marco.

By now, Marco can no longer tell if he is dreaming or really awake...

His mother sends him up to his room, where Keith is waiting for him. Marco tells Keith that he gives up, that he will do whatever Keith wants. Keith gets very excited and tells him that he is going to go down to the basement and work up a list of all the things Marco will have to do for him. But first, Keith opens his mouth and vomits out all his veiny yellow insides. The narrator screams and wakes up with his mother comforting him. She tells Keith, the narrator, that he should not have gone and played softball with Marco, and that just because Keith lives in the basement and looks like a human, he is still a monster and can still get hurt. Keith relaxes and vomits up his insides, which makes him happy.

Marco comes downstairs and sees Keith in the basement. Keith tells Marco that it's all a dream, it's only a dream...

Trivia

 * Though confusing, it seems that Keith is dreaming about Marco, who dreams about Keith. Or that this entire book was Keith's Dream.
 * This book was never made into a television episode for the Goosebumps television series.
 * The last three books in the series are out of print, and I Live in Your Basement!, along with Monster Blood IV, Werewolf Skin, and Legend of the Lost Legend only exist in first editions and were never reprinted.