The Horror at Camp Jellyjam

 The Horror at Camp Jellyjam was the thirty-third book in the Goosebumps book series. It was preceded by The Barking Ghost and followed by Revenge of the Lawn Gnomes.

The tagline on the front cover was, Tennis... Ping-Pong... Monsters, anyone?

It was first released in July 1995.

Plot
Wendy and her younger brother Elliot are on a route to a family vacation with their parents. The Wyoming countryside does very little to excite the two children, so Wendy suggests that maybe they could ride in the trailer hitched behind their car. Once inside the trailer, the two children merrily pass the time as the trailer accelerates down the highway. Wendy thinks they're going awfully fast and assume that their mother has taken the wheel.

The trailer races off the road and finally tumbles to a stop on the outskirts of a campground. The two children are unscathed, and Elliot cheerfully declares that the experience was "better than Space Mountain!"

They hear a knock at the door of the trailer and assume it's their parents. However, upon opening the door, they are greeted by a smiling blond man dressed all in white. His t-shirt is tucked into his shorts. He introduces himself as Buddy and directs their attention to the camp banner above their heads: King Jellyjam's Sports Camp. He cheerfully tells the children that they can wait for their parents in the camp.

Buddy informs the children that he's Head Counselor of the camp. Wendy asks what the little cartoon purple glob on the banner is supposed to be and Buddy tells her that's the mascot, King Jellyjam. Buddy shows them the campground. There are two long, two-story white dorms on either side. In between are various courts and sports diamonds and two swimming pools. Wendy and Elliot are excited about the prospect of playing sports. As Buddy leads the way through the camp, a little redhead girl pops out from behind a tree trunk and tells Wendy to get out of the camp while she can. Before Wendy can respond, the girl disappears.

The camp's slogan, "Only the Best," is slapped everywhere around the grounds, appearing right below the blobby face of King Jellyjam. Numerous cheerful counselors roam the grounds, including one named Scooter, who welcomes Elliot to the boys’ dorm.

Wendy makes small talk with Buddy on the way to the girls’ dorm, casually asking him where he's from. Buddy can't remember. As they walk, they pass a lot of children playing a lot of sports, from baseball to outdoor bowling.

Wendy's new female counselor, Holly, greets her. Sporting purple lipstick and matching purple fingernails, she asks if Wendy's ready for to play some sports. Wendy says she is and Holly shows her to her room. The room is decorated with nothing but some bunk-beds and a framed photo of King Jellyjam. Holly tells her that her new roommate, Deirdre, is busy playing sports. Holly leaves Wendy by herself in the room. Wendy wonders where she's supposed to go next. Before she can give it too much thought, she hears several hushed voices outside her door. The voices cry out, "Let's get her!" Three preteen girls bust into the room giggling.

The three girls are Ivy, Jan, and Deirdre. One of the girls massages her calf muscles, while Deirdre gives Wendy one of her swimsuits so she can participate in the four-lap race. When Wendy tells the girls that she's not interested in competing, they get very irate and repeat the camp slogan, "Only the Best."

Wendy and about a dozen other girls stand on the cusp of the Olympic-size swimming pool. Deirdre tells Wendy that she should have tied her hair back so it won't slow her down in the water. Once the race begins, Wendy is actually on her way to winning when she sees Deirdre working really hard to come in first. Since Wendy doesn't care, she lets her win. Deirdre is awarded a gold King Coin for coming in first. Apparently when a camper accumulates six King Coins, they get to walk in the Winners Walk. Deirdre is very excited, as she only needs one more King Coin to achieve this goal.

Holly runs up to Wendy and lectures her for not following the camp slogan. Wendy pretends she didn't throw the race but Holly knows better and tells her that the slogan is a threat, not a promise, and tells her not to do it again.

Elliot shows up and invites Wendy to watch him play ping pong in a ping pong tournament. Elliot really wants to win and gets very worked up. In the past when he gets overexcited, Wendy performs a special whistle to alert him to calm down. She is forced to use the whistle on Elliot during the tournament. He gives her two big thumbs up. Elliot wins the ping pong tournament and hopes to win another King Coin before the night is over.

The ground starts to shake and Wendy freaks out, thinking it's an earthquake, but no one else in the camp notices or cares. According to Buddy, the ground shaking at Camp Jellyjam is a common occurrence and everyone here has gotten used to it.

Wendy is getting concerned that her parents might be worried about her and her brother. She decides to call their home answering machine and leave a message for them. Before she does though, Deirdre shows up with her sixth King Coin and will be in the Winners Walk that night. Wendy gets very excited about Deirdre's excitement and decides she is going to try to win a King Coin of her own. She gets so excited that she forgets to make the phone call. That night, Wendy, Ivy, and Jan watch the Winners Walk ceremony outside in the dimly lit evening. The counselors go all out for this ceremony, and Wendy is told it is a big deal. Two counselors come out holding torches and the children who won their sixth coin follow them single file into the darkness as marching band music plays from the loudspeaker.

The girls gather some snacks for Deirdre's celebration party back in their dorm room. Ivy and Jan and Wendy pass around a bag of tortilla chips and share a can of Diet Coke while they wait for Deirdre to show up to her own party. When she never arrives, the girls decide to break the camp's curfew and go out looking for her.

The three girls wander around in the dark for a while. Some bats show up to drink from the swimming pools. Suddenly, the girls hear a cry for help-- it's the little redhead girl who previously warned Wendy. She tells the girls that her name is Alicia and she followed the counselors to see where they go. What she saw was so horrible that she insists they all must leave the camp while they still can.

Safely back inside the dormitory, the girls discover all of Deirdre's belongings have been removed. The next morning at breakfast, Wendy accosts Buddy, who tells her that Deirdre left, as did Alicia. She tries to tell Jan and Ivy, but they're rushing off to play more sports. Wendy reattempts her phone call to her parents, but is shocked to discover that the pay phones are not functional. Buddy watches her from afar and then approaches to tell her that she must find a sport in which to participate. Since she's not a self-starter, he's lined up an itinerary for her.

Wendy loses her tennis game to a girl who wins her sixth King Coin. After tennis she is hustled down to the softball diamond. She practices her swings with the bat and accidentally slams the bat right into Buddy's chest. Despite the sickening "eggs breaking" sound it makes against his chest, Buddy does not feel any pain from getting hit and cheerfully recommends that Wendy try a lighter bat.

That night, another Winners Circle ceremony. The next morning, another revelation that the winners have disappeared. Wendy tells her brother that they have to run away from the camp that night, but Elliot's in no rush: he's won his fifth King Coin and wants to acquire the sixth so he can march in line behind a torch.

Wendy covertly follows the counselors after nightfall after she notices all of them heading towards the woods. In the woods, positioned in a clearing, she finds a small white domed building and goes inside.

Inside the building she finds a small theater. Wendy ducks into a broom closet and watches as Buddy hypnotizes the rest of the counselors and himself (the nightly hypnotizing explains why Buddy didn't react to the pain of getting hit with the bat and why the other counselors are pushing the children to do well in sports). He tells the counselors that they must always serve The Master.

Wendy sneezes loudly twice. Panic-stricken, she discovers that she's not hiding in a broom closet but a passageway and escapes. She hoofs her way downstairs, noticing a foul stench rising up the stairwell.

Once below the ground, Wendy sees dozens of children working hard. All of the Winner Circle champions and Alicia are moving furiously with mops and hoses around an enormous purple gelatinous creature. Wendy spots Deirdre and runs over to her. Deirdre explains that only the best workers get to be King Jellyjam's slaves. The creature can't stand his own stench so he makes the children constantly rinse and mop him clean. Small things fall from the heights of his being onto the children: snails. The creature's face is covered in snot and it's wearing a gold crown. When it belches, the ground shakes.

Deirdre tries to get Wendy to flee, because King Jellyjam had already eaten three children that day. Wendy runs out of the igloo and sneaks into the woods, where she falls asleep. When she wakes up she hears the sound of the track meet. Elliot was going for his sixth King Coin! Wendy has to stop him so she tries the whistle, but he ignores her. So she simply tackles him to the ground just as he approaches the finish line. He grasps that she's desperate and agrees to follow her down to see the horrible creature. Once beneath the ground again, Wendy reveals that she has a plan. She tells all of the slaves to get down on the floor. Wendy watches as the creature flails and tries to pick up the children to eat them. Her "plan" is working, except that from her position on the stairwell, she isn't laying flat on the ground. The creature picks her up and lowers her towards its gaping maw. However, the monster quickly begins to melt. Wendy's plan was to stop washing the creature, making it choke on its own stench. The creature melts down to purple goo.

The children rush out of the igloo and face a group of the counselors, who are about to attack when the police show up. The stench was so bad that the cops came to investigate. Wendy and Elliot are reunited with their parents. Two weeks after the events of the camp, Buddy knocks on their door. He gives Elliot his sixth King Coin, telling him he earned it. Wendy is nervous about Elliot accepting his sixth coin. Suddenly, a foul odor fills the room--but it's revealed that it's only her mother cooking brussel sprouts.

Trivia

 * This book was never made into a television episode for the Goosebumps television series.