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Monster Blood is the third book in the original Goosebumps book series, and the first book in the Monster Blood saga. It was first published in 1992. The book follows Evan Ross and his friend, Andy, who discover the disturbing secret about Monster Blood, novelty slime which makes people and animals grow bigger like giants. The book was later followed-up by three sequels: Monster Blood II, Monster Blood III, and Monster Blood IV.

The cover illustration shows Monster Blood oozing down the stairs as a pair of glasses are visible.

In the 2008 reprint, A humanoid blob of Monster blood is emerging from a trash can with stuff in it.



While staying with his weird great-aunt Kathryn, Evan visits a funky old toy store and buys a dusty can of monster blood. It's fun to play with at first. And Evan's dog, Trigger, likes it so much, he eats some! But then Evan notices something weird about the green, slimy stuff--it seems to be growing. And growing. And growing. And all that growing has given the monster blood a monstrous appetite...


Twelve-year-old Evan Ross is being left in the care of his great-aunt Kathryn while his parents search for a new home in Atlanta, Georgia. Kathryn is eighty-years-old and is highly eccentric: she laughs at her own jokes, she argues with her cat, and she carries a butcher knife around, which frightens Evan. She's also deaf.

Evan's mother leaves the family dog Trigger with Evan to keep him company, and she gives him $10 to buy something nice. After just a few minutes of being in the house, Trigger and Kathryn's cat, Sarabeth, get in a fight, which prompts Kathryn to demand that the dog stay outside. She created a pen for him before Evan's arrival suspecting there might be issues.

Evan decides to take Trigger for a walk. Out in the neighborhood, he meets a girl his age named Andrea, who likes to be called Andy. She needs to buy a present for her cousin and invites Evan to town with her to show him around. The two enter an old toy store called Wagner's Novelties & Sundries. There, Evan finds a tin can of Monster Blood. The can's labeling markets it as a miracle substance. When Evan tries to purchase the can, he is discouraged from doing so by the shopkeeper, but Evan insists on buying the substance anyways. The shopkeeper reluctantly sells it to him for $2. Evan and Andy take the can back to Kathryn's house. Kathryn grabs the new toy, reads the label, and mutters something Evan can't hear. Then, she hands it back to Evan and whispers, "Be careful."

Evan and Andy go up to Evan's bedroom and open the Monster Blood. They find it cool to the touch. The substance glows in the dark, stretches, and bounces. Soon after playing with it, they realize that Monster Blood stains the walls and floors, so they take it outside. They bounce the Monster Blood too close to Trigger, and despite Evan's commands for Trigger to drop it, Trigger eats some of the Monster Blood.

The Monster Blood and Trigger double in size each day. Trigger grows the size of a pony. The Monster Blood outgrows each container Evan puts it in. What's more, the formerly cold substance is now warm to the touch, bubbles, and breathes. The Monster Blood is alive.

Evan runs into troubles with some neighborhood bullies: Rick and Tony Beymer, twins who Andy describes as "out of control." Evan is saved from being beaten up first by Andy, who the twins push to the ground and steal her bike, and then by an overgrown Trigger who chases the bullies for blocks. Evan visits Andy one evening to get her to take some of the Monster Blood because it's grown so much he can't keep it all, and on his way home, the Beymer twins punch him in the stomach and face. Evan has bigger troubles, however: the Monster Blood is growing out of control.

Evan returns home and puts the Monster Blood in an old tub in his great-aunt's basement. While down there, Sarabeth, the cat, pounces on Evan from behind, pushing him into the tub. The Monster Blood sucks and pulls on him but he eventually is able to free himself. The next morning, he tries to tell his aunt Kathryn about the Monster Blood by writing her a note, but she laughs at him out loud, and then whispers, "I told you to be careful."

Evan and Andy try to take the Monster Blood back to the store, but find that it has gone out of business and has closed permanently. They return to Kathryn's home and put the Monster Blood in a trashcan with a latch. Kathryn comes out of the house and tells Evan that his mother has sent a telegram and will pick him up that afternoon. In excitement, Evan runs to Trigger and finds that the dog has doubled in size again. When he opens Trigger's pen, Trigger runs out and down the street. Evan tries to chase the dog but accidentally knocks over the can of Monster Blood.

The Monster Blood rises on its own like a wave, unable to be contained now, and descends down on Evan and Andy. The two run down the street to get away from it. The Monster Blood starts chasing them by rolling and sucking up everything in its path, including a robin and the Beymer twins. Evan and Andy lead it back to Kathryn's. Kathryn comes outside, sees the Monster Blood, and runs back inside. The Monster Blood follows her into the house and Evan and Andy hear her scream. The kids rush inside.

Kathryn tells Evan and Andy to run and save themselves, that she created the Monster Blood, and she should die for it. Evan, recalling her muttering something over the tin can of Monster Blood, accuses her of putting a spell on the Monster Blood to harm him, and Kathryn admits to it, says that she made her do it. She points in Andy's direction, but it turns out she is pointing at the cat, Sarabeth, behind Andy. Sarabeth turns into a human woman in a cloak. Kathryn states that she has been Sarabeth's slave for over twenty years, and that Sarabeth took away her hearing to make her more dependent on Sarabeth. She said it all ends here, however, because she is going to throw herself into the Monster Blood.

Sarabeth says that the kids will die regardless, because they know too much. Sarabeth commands the Monster Blood to attack Evan and Andy, but before it can move, Trigger rushes in and pushes Sarabeth into the Monster Blood. Trigger immediately shrinks back to normal size, and the Monster Blood shrinks to a tiny drop, freeing everything it swallowed except for Sarabeth, who is nowhere to be seen. The robin and Beymer twins rush outside. Evan's mother rushes in, curious why the Beymer kids came running out the door like that, and Kathryn, who has regained her hearing, takes her to the kitchen to tell her the whole story.

Evan and Andy say their goodbyes and promise to stay in touch. Andy asks Evan if she can keep the last drop of Monster Blood as a souvenir, but as she reaches for it, it's gone.

Reprints and rereleases


  • The Classic Goosebumps reprint changes Evan thinking "She was pretty" to "She's pretty". This was likely because it would not make sense for Evan to think in past tense. For similar reasons, "She wasn't the shy type" becomes "She's not the shy type".
    • "His legs suddenly felt heavy from fear" removes "suddenly";
    • "feeling twins" is changed to "fleeting twins".

International releases

Classic Goosebumps


  • In the French release, this is the forty-third book in the original series.
    • Evan Ross is changed to "Ivan Ross."
    • Kathryn is changed to "Catherine."
    • Andy is changed to "Dom."
    • Trigger is changed to "Tiger."
  • In the UK, this is the fifth book in the original series.
  • The original Mexican cover used a light green slime border instead of blue, which closely resembles Monster Blood.
  • The Dutch version of Monster Blood has a few differences from the original book.
    • Evan is replaced by a girl named Steffie and Andy is replaced by a boy named Mathijs.
    • Sarabeth is a hypnotized cat and Kathryn is an evil witch.
    • The twins never got spit out. This means that they are dead.



TV series

Monster Blood was adapted into an episode of the Goosebumps TV series, as the fifteenth episode of season two. It received a follow-up titled "More Monster Blood", which is unrelated to the book's sequel, Monster Blood II.


Audiobook Release date Length Narrated by Published by
Monster Blood (Classic Goosebumps) audio book.jpg
Play in Spotify
August 2015 3 hours, 2 minutes Kirby Heyborne Scholastic Inc.




  • R.L. Stine has stated that he was inspired to writing the story after his son used to play with his toy slime.
  • This book references Nintendo, Indiana Jones, Trigger, and Hopalong Cassidy.
  • This is one of the few Goosebumps books written in third-person, which was eventually phased out as the series continued. Interestingly, all four Monster Blood books in the original series retain the third-person perspective. The Goosebumps HorrorLand book Monster Blood for Breakfast! would be the only Monster Blood book so far to buck that trend.
  • Monster Blood acts similarly to the 1958 B-movie, The Blob, in that it is a slimy mass that grows and devours everything in its path. This movie was mentioned in the first Goosebumps movie.
  • First edition copies of this book do not feature a number on the book spine.
  • The first order form featured this book as the fourth on the list, not the third.
  • Early versions of The Ghost Next Door advertise this book on the back cover instead of The Haunted Mask.
  • For a limited time in 1996, KFC in Canada offered this book for $2.29 with the purchase of a meal. Copies of this version featured a giant YTV logo on the cover.

References in other Goosebumps media

The 2005 Chillogy cover.