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 … Devon Werkheiser, John DiMaggio, Jim Belushi, Billy West, Dan Castellaneta, Debi Derryberry, Scott Menville Added on HBO 2022-07-28.