Crazy Joe Davola is noted for stalking Jerry, for whom he develops a pathological hatred. They meet him at the NBC offices (Joe, a writer, is dropping off a script, which is rejected, which he blames on Jerry). He and Jerry knew each other before with Jerry disliking him due to his extreme instability.
Elaine once dated Joe's psychiatrist (Dr. Reston), who is concerned about Joe not taking his medication. She also inadvertently dated Joe while trying to break up with the doctor, not knowing he was, in fact, the same Crazy Joe Davola terrorizing Jerry.
She becomes a target, and in a surprisingly tense scene for a comedy series (The Opera), she finds herself trapped and cornered in the psychotic Joe's apartment and only escapes after spraying Binaca in his face.
Crazy Joe Davola blames all his problems on Jerry, even ones such as getting a hair on his tongue. He nailed Kramer in the head with a roundhouse kick for not inviting him to a party. Kramer was not hurt because he happened to be wearing a motorcycle helmet, formerly owned by Newman.
Crazy Joe Davola is in exceptional shape. Tall and muscular, he keeps fit by lifting weights (sometimes while crying) and practices martial arts, which he uses (while dressed as Canio from Pagliacci) to beat a gang of hooligans in Central Park unconscious.
* Diagnosis Murder