Christopher Pike's Chain Letter

In episode four of Teen Creeps, Kelly & Katai cover Chain Letter by Christopher Pike (1986)."This week Kelly and Katai cover Chain Letter! Chain letters are so much more than those emails your aunt forwards you! Subscribe, or you'll be cursed with bad luck in love for seven years!"

Description
From Goodreads: When Alison first read the chain letter signed "Your Caretaker," she thought it was some terrible sick joke. Someone, somewhere knew about that awful night when she and six other friends committed an unthinkable crime in the desolate California desert. And now that person was determined to make them pay for it. One by one, the chain letter was coming to each of them ... demanding dangerous, impossible deeds... threatening violence if the demands were not met. No one out of the seven wanted to believe that this nightmare was really happening to them. Until the accidents started happening -- and the dying...