The Give Yourself Goosebumps book where you join a club.
You are the new kid in town, and you have trouble making friends. One day, a kid named Nick informs you of a club he is in called the Horror Club. The Horror Club meets late at night in an old mansion called Bat Wing Hall, which is said to be haunted. The members of the Horror Club are going on a scavenger hunt to find out if Bat Wing Hall is really haunted. You are asked to pick which team to join from there.
If you join the Red team, you discover your teammates are monsters. If you join the Blue team, you get turned into a bat. Either way, you must try to escape Bat Wing Hall alive.
Trapped in Bat Wing Hall provides examples of:
- Admiring the Abomination: In the Blue Team Storyline, you can encounter the ghost of Bat Wing Hall, Professor Krupnik, and get him to reveal himself to your friends so he can scare them into not returning and then he'll lift your curse. But when they see him your friends instead exclaim, "Cool, a real ghost!"... at the end of the story, the ghost of Krupnik ends up an honorary member of the Blue Team and one of your best friends.
- Animorphism: This book stands out, showing the changed form (a bat) on the cover. One bad ending from the Blue Team scenario have your friends Marcie, Lara and Martin getting turned into bats as well.
- Bat Scare: The cover shows a scary-looking bat about to attack the reader.
- Cassandra Truth: In the Blue Team storyline, you're given the option to attempt convincing your new friends that Bat Wing Hall really is haunted. It doesn't work.
- Children's Covert Coterie: The Horror Club, a secret group of local kids known for convening in the eponymous mansion for scavenger hunts. Their true nature depends on which of the two main plotlines you choose: in the Blue Team plotline, the Horror Club are just thrillseeking children trespassing on an abandoned building, in which case they end up becoming potential allies when you end up getting turned into a bat... but in the Red Team plot, the Club is a gang of monsters in disguise, either seeking prey or looking for new members to convert into monsters.
- Dead All Along: This actually happens to you in one ending. You are given a boat ride by a figure who (while never referred to as such) is clearly the Grim Reaper based on the book's description, and when the ride ends you are at a crypt, and realize that you can see through your own body, and your name has been written on the crypt.
- Dem Bones: Your first task in Nick's treasure hunt is to collect a human bone, which you obtain from the skeleton of a severed human hand in a box - in one of the (surprisingly, good) endings you come across a sentient skeleton with one hand ending in a stump trying to stop you from leaving, but you managed to flee from it before escaping Bat Wing Hall.
- Failure Is the Only Option: If you choose to return to the cemetery immediately after being turned into a bat rather than waiting until morning, all further choices either lead to a bad ending or result in you waiting until morning anyway.
- Forced Transformation: Most of the bad endings in the Red Team story end with you transforming into a monster, while the Blue Team storyline involves you turning into a bat due to a curse, forcing you to break it before it's too late. The best ending of the Red Team storyline reveals this also happened to their own members thanks to another curse and successfully completing the scavenger hunt helped to break it.
- Go-Karting with Bowser: One scenario in the Red Team storyline — AFTER you discover Nick and your new friends are actually hostile monsters — have you catching them playing your favorite video game and deciding to challenge Nick to a video game duel. If you win, you can leave Bat Wing Hall and return home; if you lose, you fail your quest on the spot, at which point you then transformed into a fourth monster. Now that you're stuck permanently with Nick and the other monsters, you then ask if he's interested in a rematch.
- Horror Hunger: If you go with the Blue Team and turn into a bat, you develop a craving for insects even while in human form. One ending has you arrested for eating rare beetles on display in a science emporium. While in jail you come up with a brand new flavor of ice cream, Beetle Berry Crunch. Three guesses as to what's the secret ingredient.
- Intercontinuity Crossover: One of the Red Team scenarios have you challenging Nick and the other monsters to a video game duel. The name of the game? "Mud Monsters".
- Nice Girl: Lara of the Blue Team is revealed to be the kindest of the three when you encounter her as a bat and discover she's looking up your phone number to invite you to hang with her friends.
- Not a Mask: One of the earliest bad endings in the Red Team storyline have Nick, Debbie and Connor revealing themselves as monsters. In a moment that crosses with Too Dumb to Live, the book actually gives you an option to grab Nick's face to see if it's a mask. It's not, and by pissing him off Nick then eats you on the spot.
- The Pig-Pen: Connor from the Red Team storyline, who is so filthy you think "he smells like a dumpster" just by standing near him. Then again, he's a monster in disguise, as you found out if you joined Nick's team.
- Puppy Love: "You" have a crush on Lara, both of you being around 11-12 years old (although the book assumes "you" are male.) Comes into play more if you do the Blue Team storyline.
- Race Against the Clock: The Red Team Storyline has the player completing a scavenger hunt before 12 midnight, or else they will be transformed into a monster forever.
- Reset Button Ending: During the Blue Team storyline, if you return to the graveyard and end up in the crypt of the Swamp Thing, the story abruptly gives you a chance to go back to the first page and start all over.
- Taken for Granite: One ending has you overhearing Debbie mentioning why new members of the Horror Club mysteriously turn to stone. Then, it happens to you.
- Time Travel: To complete the Red Team storyline, the player will need to travel all the way back to Ancient Egypt to recover a necessary component for the scavenger hunt, and then travel back to the present. Unfortunately, a poor choice might lead to the player returning to the timeline... AFTER midnight, and then turning into a monster and failing the whole adventure.
- Was Once a Man: One of the really good endings if you pick the red team storyline is that, by successfully completing the scavenger hunt, you've transformed Nick, Debbie, and Connor into humans. Nick then starts telling a story about a group of kids who were turned into monsters and could only be saved if someone completed a really dangerous hunt...
- What Happened to the Mouse?: Right in the first page, you befriend Nick, who invites you to a haunted house gathering; you're given the option to stay on Nick's team, which is Red, or follow the partner team instead, which is Blue. If you choose to follow the Blue Team, you will NEVER mention Nick again for the rest of the story, even in the sub-plot where you can choose a friend to help you after being turned into a bat. Inversely, if you choose the Red Team, the Blue Team members disappear and are never mentioned again.
- If you get the ending where you decide to create a new ice cream flavor, you become rich thanks to its success... but the book seems to skip over the fact that you're still afflicted by the curse.
