"Good Friends" was the fifth short story featured in the book, Tales to Give You Goosebumps.
Dylan and his friend, Jordan are killing time after school, shooting hoops in Dylan's front yard. Dylan is a little worried that his older brother, Richard, is going to get onto him for playing with his friend instead of doing his homework.
Then his little sister, Ashley, shows up. The two boys make fun of her, since she has an imaginary friend named, Jacilyn. Dylan and Jordan pretend to tie Jacilyn to a tree and then Jordan suggests the two actually tie up Richard with duct tape and rope.
Jordan gives Dylan the idea of taking Richard's two pet tarantulas, Axel and Foley, and scaring Ashley with the spiders. They're even going to tell her that one of the spiders ate Jacilyn. Just as they're about to make their move, Richard stops Dylan, who is holding the tarantulas, and tells him to quit playing with his imaginary friends, Jordan and Ashley...