Purple Peanut Butter

Purple Peanut Butter is a purple goo that smells similar to peanut butter. In Beware of the Purple Peanut Butter, if reader chooses to snack on the goo, they gradually shrink after consumption.

Beware of the Purple Peanut Butter
The reader will have to spend the summer with their aunt and uncle. That means that the reader will have to spend time with their cousins, Barney and Dora. During a game of hide-and-seek, the reader discovers a fridge in the basement. Inside the fridge, there is a slice of cake from a place called "Effy's Bakery" and a container filled with a purple substance. Strangely, the substance smells like peanut butter.

If the reader chooses to eat the Purple Peanut Butter, they will slowly start to shrink down every few minutes. There is never an explanation for where the Purple Peanut Butter came from.

Goosebumps: The Game
The Purple Peanut Butter appears in Goosebumps: The Game. It can be found in the cabinets of the kitchen inside Dead House. Strangely in the game, it's just normal peanut butter, besides its color.

Trivia

 * Purple Peanut Butter seems to be the polar opposite of Monster Blood. Unlike Monster Blood, which makes causes growth after consumption, it makes things shrink when consumed.
 * If chosen to eat by the reader, the book describes the purple peanut butter to have an "awesome flavor" and taste like "all the best desserts." If the reader eats it after they have eaten the stale chocolate cake, the book describes it as tasting awful, like a "combination of Brussels Sprouts and liver."