Cosmo Kramer is Jerry's crazy neighbor across the way in his apartment complex.  Krmaer is a ridiculous human being who is constantly known for barging into Jerry's apartment and eating all his food.  Though Kramer never has a steady job, he is constantly scheming throughout the series whether it's making a coffee book about coffee tables or co-creating the Bro with Frank Costanza.

Cosmo Kramer Quotes

Punk Dude: Hey Kramer, have you ever killed a man?!
Kramer: What do you think Junior? You think these hands - they've been soaking in Ivory Liquid?

Jerry: "Quone"?
Helen: 3031
Jerry: "Quone"? No, I'm afraid that I'm going to have to challenge that.
(Jerry picks up the dictionary.)
Helen: 32
Kramer: No, you don't have to challenge that. That's a word. That's a definite word.
Jerry: I am challenging.
Kramer: Quone. To quone something.
Jerry: Uh-huh.
(Jerry looks up the word.)
Helen: I'm not playing with you anymore.
Morty: Quone's not a word.
Jerry: No good. Sorry. There it is. Get it off.
Helen: (to Kramer) Why did you make me put that down?
Kramer: Nah, we need a medical dictionary! If a patient gets difficult, you quone him.

Seinfeld Quotes

Elaine: (referring to Dr. Reston) He's like a Svenjolly.
Jerry: Svengali.
Elaine: What did I say?
Jerry: Svenjolly.
Elaine: Svenjolly? I did not say Svenjolly.
Jerry: George?
George: Svenjolly. (licking some peanut butter off his finger)
Elaine: I don't see how I could've said Svenjolly.
Jerry: Well, maybe he's got, like, a cheerful mental hold on you.

Because I'm like ice, buddy. When I don't like you, you've got problems.