On Wednesday night's "Law & Order: Special Victims Unit," Detective John Munch, played by Richard Belzer, retired. And in a fitting send-off the fictional cops of New York's 16th precinct threw him a roast. Belzer's time playing the perpetually sunglasses-wearing detective is unique in broadcast television, in that he's played the same character on 10 TV shows across five channels and 20 years. While Belzer's run ties with Kelsey Grammer as Dr. Frasier Crane and James Arness as Marshal Matt Dillon on "Gunsmoke" for longest portrayal of a single character on TV, the breadth of Belzer's apparances sets him in a league of his own. Belzer was known primarily as a stand-up comedian when he was cast as a detective in the highly acclaimed NBC police drama "Homicide: Life on the Street." The show debuted in 1993 and aired for seven seasons. He joined the cast of "Law & Order: Special Victims Unit" in 1999 after "Homicide" ended and has played Munch there for 15 seasons, rising from senior detective to sergeant and finally on to DA special investigator in his final episode. But in addition to being a regular on those series, he's also made guest appearances as Munch on "30 Rock," "The Wire," "Law & Order: Trial By Jury," "The Beat," "The X-Files," "Jimmy Kimmel Live," "Arrested Development" and, one of Belzer's favorites, "Sesame Street." In a farewell essay he wrote for the Huffington Post, Belzer took special note of the sunglasses-wearing John Munch puppet that Sesame Workshop built for the occasion. While Belzer is indeed leaving the show, a spokesperson for NBC indicated that the door was open for the Munch character to work with the SVU squad in the future. To commemorate Munch's retirement, NBC has released the extended version of the Munch roast. Fans of the character's long history should keep a special eye out for a cameo from Clark Johnson, who played Munch's Baltimore colleague, Meldrick Lewis, on "Homicide."