Scary Birthday to You!

Scary Birthday to You! is the thirty-ninth book in the Give Yourself Goosebumps gamebook series. It was published in 1999.

The cover illustration depicts a white birthday cake with blood-red icing. The blue candles on top are giving off a big blaze of fire. A section of the cake had been cut away, revealing that it was filled with all sorts of creepy crawlies, such as worms, a large spider, and other bugs. A brown-furred rat is seen gripping the sides of the cake.

Blurb
IT'S YOUR PARTY, YOU CAN SCREAM IF YOU WANT TO!

Your parents have to work on your birthday, but don't worry—they've hired some guy to create a special "horror birthday party" for you. Uhh... can you say "lame"? They must have forgotten you're turning twelve, not two!

But then Dr. MacDeath arrives and twists your friend into a live balloon animal! Now you have two choices: open your presents or play party games. If you open presents, you could be the proud owner of a vicious wolf! If you decide to play paintball, you end up dodging paint capsules—filled with acid!

The choice is yours in this scary GOOSEBUMPS adventure that's packed with over 20 super-spooky endings!

Plot
Your parents have to go to work on your birthday. They hire a strange entertainer called Dr. MacDeath to throw you a horror-themed birthday party, but he soon proves himself to be evil, and turns one of your friends into a balloon animal. He nails shut all the doors in your house so you can't escape. After an interruption from someone at the door, he forces you to cut your birthday cake, which turns out to be crawling with bugs and worms. You must then decide whether to play party games or open presents.

Story A
You play party games, with a choice between Paintball, Dodgeball, Pin the Tail on the Donkey, or a Scavenger Hunt. You have to survive the games and find a way to beat Dr. MacDeath, but he's not exactly playing fair.

Story B
You decide to open presents. Your friends' presents have been enchanted by Dr. MacDeath, but he has a few surprises of his own for you.

Side story C
In story B, you open a present Dr. MacDeath gave you, which contains two tickets to a horror-themed amusement park. You take your friend Josh with you and can have fun without MacDeath, but this just leads to two possible endings (one good, one bad.)

List of endings
There are sixteen bad endings and six good endings.

Bad endings

 * Non-ending: Dr. MacDeath is revealed to be an insane entertainer who kidnapped the clown your parents originally hired; the clown got free and called the cops so they arrested Dr. MacDeath. Your friends make fun of you and leave. You blow out your candles and wish to have your birthday start over again, but this sends you back to the start of the book.
 * You decide to play "Pin the Tail on the Donkey." The cardboard donkey comes to life as a dog with many tails. The dog likes you, but you are smothered to death as it wags its tails in your face.
 * During a game of paintball, you're killed when Dr. MacDeath sprays acid all over you.
 * While playing paintball with Dr. MacDeath, you switch weapons with him, but whatever was inside his weapon makes him grow to a giant size. He slips on paint and falls over, crushing you and all your friends to death.
 * Dr. MacDeath throws a bomb at you. You try to dodge, but you're killed in the explosion.
 * Dr. MacDeath's bomb turns out to be a stink bomb that is so disgusting that he and all your friends leave the party. You're stuck on your own, and the house still smells terrible.
 * Non-ending: You decide to challenge MacDeath and tell him his game isn't fair. The book mocks you for thinking he would care about that, and says that you are too silly to continue with the story.
 * During the scavenger hunt you climb out onto a tree branch, which breaks under your weight, apparently killing or seriously injuring you.
 * Dr. MacDeath lynches you with the noose you brought back from the scavenger hunt.
 * You blow out your candles and wish to be as far away from Dr. MacDeath as possible. Your wish comes true, and you end up in a remote village in an unknown foreign country.
 * Dr. MacDeath announces that he has to go to his next party, but promises to "see you tomorrow." When you arrive at school the following day, MacDeath turns out to be your new principal. Although you survive the story, this ending is presented as bad because you have to deal with an intimidating authority figure at school.
 * You try to dig up a grave to collect the human bones that you need for the scavenger hunt, but a ghost grabs you and drags you into the grave.
 * You're hired at a horror-themed park to re-record all the scream effects, but they do horrible things to scare you, like create a fake version of Josh's corpse, so your screams will be real.
 * You try to dig up the severed head's body, but it escapes and runs away down the road. So the severed head takes your body instead.
 * Your present from Dr. MacDeath turns out to be a box, inside another box, inside another box...You are told that there is no end to the boxes.
 * Your friend gives you a birthday present that turns out to contain a stuffed toy wolf. Dr. MacDeath makes it come to life, and it bites your hand off.

Ambiguous endings

 * Dr. MacDeath turns out to be the uncle of Sarah, the latter of whom reveals that she can willingly twist herself into a balloon animal. Sarah's uncle is merely pulling horror-themed pranks on you, not meaning any harm. However, the crotchety old lady next door decides your party is getting out of hand, and sends everyone home (with the approval of your parents who had asked her to keep an eye on things). This ending is ambiguous because even though you survived, you do not get to completely enjoy your birthday.
 * You complete the scavenger hunt, forcing Dr. MacDeath to leave. But then another entertainer shows up at your door, so it may not be over just yet. This is ambiguous because this next entertainer may be just as bad as Dr. MacDeath (or worse).

Good endings

 * You and your friends cover Dr. MacDeath in paint. This makes him look silly instead of scary, and he's so annoyed that he leaves the party, so you're free to have a paintball war with no parents around.
 * You become Dr. MacDeath's assistant, slowly changing his potentially dangerous party ideas into safer and hence more enjoyable ones. You then become more beloved than Dr. MacDeath to the point of replacing him completely, you have now become the life or in this case, the ‘death’ of the party. This ending is described as the "happiest end of all".
 * Josh gets trapped in a ballroom with dancing ghosts. He joined them because he thought it would be "fun" to learn the waltz. You decide he is too dull to be worth saving, and escape on your own.
 * You wish on your birthday cake for the severed head to be reunited with his body. The person comes back to life. He is Dr. MacDeath's father, and the two of them planned this so that you would wish for him to be restored to life. As a thank-you, he gives you an electric car big enough to drive your friends in.

Trivia

 * The tagline, "It's your party, you can scream if you want to!", is a reference to the lyrics of the Lesley Gore song "It's My Party".
 * The title of this book is a play on the song "Happy Birthday to You".
 * This would be the first of two books in which the title is a play on "Happy Birthday to You". The second being the Goosebumps SlappyWorld book Slappy Birthday to You.
 * Dr. MacDeath's moral alignment varies throughout the book. Depending on the reader's choices, he may be either a malicious individual or a good-natured birthday entertainer who only seems frightening.
 * Some promotional material referred to Dr. MacDeath as just "Dr. Death." Either this was a typo or the name was changed before publication.
 * Horror Place could be a reference to HorrorLand.
 * Story A is notably longer than Story B.
 * In most installments of the Give Yourself Goosebumps series, the reader is punished if they leave a friend, a relative or another potentially helpful character to a bad fate. During Side Story C, however, the reader can get away with abandoning Josh.
 * Page 26 contains a typo: the word "your" is misspelled as "you", creating the sentence, "You heart hammers as you enter the ballroom."
 * Page 28 contains a typo: the word "sigh" is misspelled as "sign", creating the sentence, "You breathe a sign of relief."