Robert Mittenthal

When Casper's been being friendly lately even when playing with a boy named Jimmy, Kibosh: The King of the Underworld has Casper enrolled into a Scare School headed by the two-headed headmaster Alder and Dash. He befriends Ra, a mummy with unraveling issues and Mantha, a zombie girl who keeps falling apart. When Casper discovers the two-headed headmaster's plot to use a petrification potion to turn Kibosh into stone and take over the Underworld and Deedstown, he and his new friends must stop him.

Andrew and his older brother Carl enjoy listening to ghost stories that the local undertaker tells them. One night he tells the tale of a local farmer whose wife gave birth to Siamese twins, one being good natured while the other was clearly evil. The farmer, ashamed of them, kept the twins locked in their room. Eventually the twins got sick and died together, so the farmer sawed them in half and buried the good twin in a cemetery and the bad twin in a shallow grave near the house. Later, Carl and his friends decide to hold a séance in the cemetery where the good twin is buried, but they unintentionally awaken the bad twin instead. Gradually, he possesses nearly everyone in town and it is up to young Andrew to stop him.