Calling All Creeps! is a novella written by R. L. Stine. It was the 50th book in the original Goosebumps book series.
Description[]
Ricky Beamer is furious when he gets kicked off the school paper. So he decides to play a joke on Tasha, the bossy editor-in-chief. Just a little joke. Harmless, really.
After school one day he sticks a message in the paper. "If you're a creep, call Tasha after midnight," it reads.
But somehow Ricky's message gets messed up. And now he's getting calls! Strange calls from kids who say they are creeps. Creeps with scaly purple skin. And long sharp fangs...