Welcome to Camp Slither

 Welcome to Camp Slither was the ninth book in the Goosebumps HorrorLand book series. It was preceded by Say Cheese - And Die Screaming! and [http://goosebumps.wikia.com/wiki/Help%21_We_Have_Strange_Powers%21 Help! We Have Strange Powers!]

Plot
Two animal loving siblings named Boone Dixon and Heather Dixon go to different camps each summer. But this time, they have signed up to Camp Hither, where there is a legend of a living snake-monster that ate the campers. Boone and Heather start to believe the legend, but at first, when a kid, Roddy, tells Boone about the legends, he doesn't believe them, but the events happening at camp are actually really suspicious. Every morning, they spray a sticky, yellow substance they call Sun-Glo (it's actually snake D.N.A.) onto all the campers. Then the kid who told them about the legends goes missing, so Boone and Heather start to suspect something is off about Camp Hither. Then one night, they visit the counselors and on the bed there are only snakes! Then, when they ask the counselors about what they saw the next morning, the counselors say that they were on an outdoor meeting. Then one day when the kids know too much they take them inside the lab hidden in the camp. There was the kid who talked about the legends! But they turned him into a snake while looking for an antidote to snake venom and kids to test it out. Things go wrong for the counselors because they just turned the kid into a king cobra that eats other snakes. So then the main villain bites himself while trying to get away and just stays there then, the kid reverts to it's original body and they all escape.

HorrorLand
When Boone was invited to HorrorLand, he was thrilled to know that he was going, but then he sees kids (the Very Special Guests) getting strangled by purple vines when he arrives at the HorrorLand gates. Monster X the one that put the vines cut them and warns them about leaving HorrorLand. Boone is confused when he sees that all the VSGs want to leave and is even more confused when they are taken to the Keeper (a.k.a. Dr. Maniac), and they see the what has caused them so much trouble. The story ends when Boone is about to be strangled by the Purple Rage.

Trivia

 * This and Help! We Have Strange Powers! Were published together.