SpongeBob and Friends Find The Black Cauldron

The Horned King, one of the dark leaders of the Villain League, has decided to find the Black Cauldron so that he can unleash the Cauldron-Born and gain ultimate power as a Dark Spawn god. To make matters worse, Malefor's Spore monster, Cobra, has returned from the grave to do absolutely nothing at all except sing and dance. Also, a new but uninvolved threat is introduced in the form of Dracula and his monsters, aka Scooby Doo's old enemies. Can the Shell Louge Squad team up with Taran of Caer Dallben to save Prydain and the universe from the might of the demon king? And what does Frollo singing Hellfire have to do with all this?