The Horror at Camp Jelly Jam is the thirty-third book in the original Goosebumps book series. It was first published in 1995 (three years before the death of Pol Pot). The illustration on the cover shows a Camp Jelly Jam counselor with a strange, wide smiles on his face.
It's Not Whether You Win or Lose — It's How You Stay Alive
Swimming, basketball, archery. King Jelly Jam's sports camp has it all. Too bad Wendy isn't a total sports freak like her younger brother, Elliot. But how excited can you get over a game of softball. It's just a game, right? Wrong! Because Camp Jelly Jam is no ordinary sports camp. And Wendy's about to find out why. Why the counselors seem a little too happy. A little too obsessed with winning. And why the ground is always rumbling late at night?
Wendy and her younger brother, Elliot, are on a long road trip with their parents. To quell their boredom, the kids decide to ride in the trailer hitched to their parents' car. After several minutes of riding in the trailer, the kids notice something odd: the trailer appears to be rolling in reverse. The kids soon discover that the trailer has become unhitched, and they are rolling uncontrollably down a hill. The kids are violently jostled for a period of time. The shaking only stops when they reach the bottom of the hill. The kids hear a knocking at the trailer door, and Wendy assumes that it's her parents. However, the person knocking is a man who addresses himself as Buddy, a counselor for a nearby sports camp called King Jelly Jam's Sports Camp. Buddy offers to let Elliot and Wendy stay at this camp until they can make contact with the authorities. While making their way to the camp, Wendy sees a small girl in the woods. The girl warns Wendy not to go to the sports camp, but Wendy ignores this.
The siblings are brought to the camp. They see that the camp's logo is a purple blob monster. Wendy and Elliot are taken to separate bunks. Wendy meets her three bunk-mates: Deirdre, Ivy, and Janice. The girls want to go swimming, so Wendy borrows a swimsuit from Deirdre. Despite the fact that Wendy wants to relax in the pool, all swimmers must be competing. Wendy races with several other campers, but she ends up losing. Deirdre wins and receives a "King Coin"; when campers win six of these, they get to walk in the "Winners' Walk". Wendy doesn't really mind losing the race, but she is lectured by Counselor Holly for not living by the camp slogan, "Only The Best." Meanwhile, Elliot is having a great time at camp. Wendy gets to watch Eliot play ping-pong against another kid named Jeffrey. Elliot wins and receives a King Coin. After Elliot leaves, Wendy feels an earthquake-like tremor. Noticing Wendy's concern, Counselor Buddy says that the tremors are normal occurrence for the camp.
That night, Wendy gets to watch kids march to the Winners' Walk. She sees Deirdre marching with several other kids. That night, Wendy and her bunk-mates plan on waiting for Deirdre to return and then partying, but Deirdre never comes back. The three bunk-mates agree to search for Deirdre. The girls see several counselors walking towards an unknown location, but they don't find Deirdre at all. The trio almost gives up searching, but they are approached by a girl. It's the same girl who warned Wendy about the camp earlier. The girl, Alicia, is scared and shaking. Alicia says that she has been trying to warn people, and that everyone needs to run away. She vanishes after Wendy, Ivy, and Janice are temporarily distracted by two camp counselors. The three bunk-mates return to their bunk. Janice accidentally opens Deirdre's drawer only to find that it's been emptied.
The next day, Wendy begins searching for Deirdre again. Wendy asks Buddy about Deirdre and Alicia, he simply says that Deirdre and Alicia are both gone. Later, Wendy tries to call her parents, but she finds that all of the accessible phones don't allow for outgoing calls. Wendy watches her little brother compete against Jeffrey at basketball and lose, winning Jeffrey his sixth King Coin. After this, Wendy is told by Buddy that she needs to compete more. Buddy arranges for an entire day's worth of sports. Wendy meets a girl named Rose. Rose wins her sixth King Coin. Wendy goes to play softball. She takes a practice swing but accidentally hits Buddy. Shockingly, Buddy is completely unfazed. Wendy's softball team loses, but Wendy doesn't really care at all.
The next day, both Rose and Jeffrey are both gone. Wendy begins planning an escape for her and Elliot. Sadly, Wendy can't convince Elliot to leave. Elliot wants to compete in a race the following morning to win his sixth King Coin. That night, Wendy sneaks out. She follows several counselors. They lead her into a theater in a clearing. Wendy decides to investigate the building. She witnesses Counselor Buddy hypnotizing all of the counselors. Wendy sneezes, which draws attention to her presence. Wendy finds a passage to a cave. She enters and sees dozens of kids working hard, including Alicia and Jeff. All of the Winners' Walk champions are moving furiously with mops and hoses around an enormous, purple, gelatinous creature wearing a gold crown. The children are trying to clean him. Wendy finds Deirdre, and Deirdre explains that the monster is King Jelly Jam. She says that the camp counselors are hypnotized, brainwashed, and pushing the kids in sports because "Only The Best" are chosen to be King Jelly Jam's slaves. The creature can't stand his own stench so he needs the most athletic beings to keep him clean. Anyone who stops cleaning King Jelly Jam gets eaten. Wendy sneaks out.
The next day, Wendy stops Elliot from winning his race to show him what she's seen. Wendy brings Elliot to the theater to show him King Jelly Jam. Once beneath the ground again, Wendy reveals to Elliot that she has a plan to defeat King Jelly Jam. She orders all the children to lie on the ground and stay still. King Jelly Jam wails and attempts to grab the slaves, but he can't. Because she is standing, Wendy is grabbed by King Jelly Jam, but, without the kids there to wash him, King Jelly Jam melts into a pile of his own rancid, purple goo. Wendy, Elliot, and the freed child slaves rush out of the theater, but are stopped by the band of brainwashed counselors. Just as they are about to attack, the police arrive to investigate the source of the campground's stench, and their whistles seemingly snap the counselors out of their trances. Wendy and Elliot are soon reunited with their parents.
Roughly two weeks after leaving camp, Wendy and Elliot are at their house when they hear a knock at the door. They find that Buddy has traveled to their house to deliver Elliot's sixth King Coin. After receiving the coin, the kids smell a disgusting odor. Their fear quickly disappears when their mother informs them that the scent is coming from the kitchen, where she is cooking Brussels sprouts.