“Do I look like a hipster doofus?” - Cosmo Kramer Cosmo Kramer (usually referred to by his last name only Kramer), played by Michael Richards, Kramer is the wacky neighbor and friend of Jerry Seinfeld. Cosmo was known only as “Kramer” for many years on the sitcom; not even Jerry knew his real first name. It was George Costanza who found out his unusual name through an encounter with Kramer’s mother, Babs Kramer, in Season Six. Cosmo appeared in all but two episodes: Season Two’s “The Chinese Restaurant” and Season Three’s “The Pen”.