The original cover illustration features Max Thompson looking through a mirror in the attic. Half his body is invisible.
The Classic Goosebumps cover illustration features a boy whose head has vanished under the light of the mirror.
DISAPPEARANCES CAN BE DEADLY.
On Max's birthday, he finds a sort of magic mirror in the attic. It can make him become invisible. So Max and his friends start playing now you see me, now you don't. Until Max realizes that he's losing control. Staying invisible a little too long. Having a harder time coming back. Getting invisible is turning into a very dangerous game. The next time Max gets invisible, will it be... forever?
Max Thompson is hosting his birthday party at his home. Among the guests are Noah "Lefty" Thompson, Zack, Erin, and April. Noah is Max's brother, and he is called Lefty because he is left-handed. Zack is Max's best friend, and he has a strange hairstyle. Erin is a loud-voiced girl, while April is incredibly shy. The party is almost finished when Whitey, Max's dog, runs to the attic. While the kids look for him, they find a large, old mirror. Max pulls the chain of an overhead light. As soon as he does this, he disappears.
When the lights go out, Max reappears. His friends and brother insist that he became invisible, although he refuses to believe the group. That night, Max returns to the attic to inspect the mirror. Lefty joins Max on this exploration. Both boys want to make themselves invisible. The boys turn on the light and disappear. After ten minutes, they begin to feel weak. They turn off the light, but it takes slightly longer for them to become visible.
The next day, the group from the party reassembles at Max's house. Erin suggests that they hold a contest to see who can be invisible the longest. April, wanting to stay visible, chooses to time her friends. Before Lefty gets a chance to go invisible, his grandparents arrive for dinner. The kids decide to postpone the contest until another day. During dinner, Lefty gets up and leaves the table. A while later, Max sees a floating fork and deduces that Lefty made himself invisible.
That night, Erin calls Max by telephone. Erin tells Max to take the mirror to school for the science fair, but he refuses. Max goes to the attic and looks at his reflection in the mirror. He hears his name being whispered from the mirror, but isn't sure if it's coming from the mirror, or if he's imagining it. Frightened, Max runs back to his room and locks himself in until the next morning. When he wakes up, Max discovers that Lefty became invisible again. Max takes Lefty to the mirror to become visible again. Once visible again, Lefty begins acting strangely.
Deciding that the mirror could be dangerous, Max call his friends and cancels the contest. However, Zack, Erin, and April return to Max's house because Lefty agrees to revive the contest. When April decides to become invisible, Whitey also becomes invisible with her. Max quickly forces both of them to become visible again. During Erin's turn, Erin remains invisible for several minutes. When she becomes visible again, Max also notices that something has changed in her behavior.
Zack remains invisible for fifteen minutes. During this time, wants to leave the house and play a prank on a neighbor. Max runs to the attic and forces him to become visible again. Strangely, Max discovers that Zack's hairstyle has seemingly been reversed. When Max tries to ask him about his hair, Erin and Zack use the mirror to make him invisible. As the minutes roll by, Max begins to feel weak. He asks to be made visible again, but Zack and Erin don't pay attention to him. A haze appears, followed by a white light and a figure approaching Max; it's his own reflection!
Max's reflection tells him that Zack and Erin have been replaced by their reflections. Zack and Erin are now locked in the mirror. Before Max's reflection can swap places with him, the duplicates of Erin and Zack make Max visible again, assuming that the change has already been completed. Suddenly, Max's reflection appears in the mirror. He tells them that the real Max escaped. The duplicates of Erin and Zack try to make Max invisible again. Max flees the attic, but he is caught by the reflections. He asks April for help, but she is also caught.
Unexpectedly, Lefty enters the attic and breaks the mirror using a softball. The reflections are sucked into the mirror's pieces, and the real Erin and Zack are brought back into the real world.
Finally, Max and his brother decide to play catch. But to his horror, Max notices that Lefty is throwing with his right hand.
Reprints and rereleases
2003 - 2007 reprint series
||April 28, 2015||Standalone||Paperback|
- The Classic Goosebumps reprint was released as a tie-in to the Goosebumps film.
- The Super Nintendo reference is removed.
- In the original printing, Erin says they could win a gift certificate to "Video World". The reprint changes this to "Pizza Planet".
- "I wanted to watch the Terminator movie I'd rented" is changed to "I wanted to watch a Terminator movie". Curiously, "They didn't like the Terminator movie" is changed to "They didn't like the movie"
- In Russia, this is the first book in the original Goosebumps series.
- In Portugal, this is the seventeenth book in the original Goosebumps series.
- In France, this is the fourth book in the series.
- Max is called "Paul."
Some pieces of apparel used the back tagline from the book, however, they replaced the word "deadly" with "scary".
- The cover artist, Tim Jacobus, did not add the cobwebs or spider in the original painting. It was added in post by an unknown artist, presumably a Scholastic employee. The 2003 reprint did not include these changes.
- Stine has said he's fond of this book — and that parts of it were inspired by the 1990 film Flatliners.
- Although it isn't a sequel to Let's Get Invisible!, the Goosebumps Series 2000 book Ghost in the Mirror follows a similar plot with children being switched with creatures from an evil mirror.
- This book references The Terminator, Super Nintendo, X-Force, Coke, Twister, Life magazine, People magazine, Saturday Night Live and Gap.
- The title of this book may be a spoof of the 1981 Olivia Newton-John song, "Physical".
- At 139 pages, this is the longest book in the original series.
- First editions of this book do not feature a number on the spine. This would be the final book to do so.
- The concept of the mirror reflections trying to take over people's lives may have taken inspiration from "Mirror Image", an episode from the 1959 TV show The Twilight Zone.
- Whitey was likely named after a dog of the same name that R.L. Stine's family owned when he was a child and was mentioned in It Came From Ohio!.
- In Cry of the Cat, a tombstone appears for a dog named Whitey.
References in other Goosebumps media
- In Goosebumps: The Game, the mirror appears with a mirror demon. After the demon's defeat, a copy of the book itself appears and can then be collected as an item in the player's inventory. The book's manuscript also appears later.
- This book's back tagline, DISAPPEARANCES CAN BE DEADLY, is used as a caption in the Monster Survival Guide.