Random Episodes
Crippled Summer
The Death of Eric Cartman
Butters is freaked out when he thinks he can communicate with the dead. Although his parents have made it clear to him there are no such things as ghosts, Butters is sure one is haunting him. Butters ... 
World War Zimmerman
This episode parodies the movie "World War Z".
In this South Park episode, Cartman is deeply disturbed by a person, which he considers to be a threat to all humanity (and it is not Kyle). Search Episodes
If you're looking for an episode but cant remember which season it's in but can remember part of the title use this.
Short searches like "cartman" usually yield best results.
