Character in Seinfeld. Said to be so charasmatic that he has had children named after him. In fact, if you know a Cosmo, he was probably created in honor of Cosmo Kramer
Cosmo: Cosmo Kramer was named after me!
Friend: We all know that's not true because everyone named Cosmo was created as a tribute to Kramer.
Cosmo: Sorry, you are right