It's not the same as an invisible Snuffleupagus, but there is something very exciting happening with Sesame Street. On August 14, a segment called "Law and Order Special Letters Unit" will premiere, starting with "The Missing M." Hal Boedeker at the Orlando Sentinel reports that the actual cast voices will be used, and Dick Wolf himself said, "I feel like a tobacco company executive, because hopefully we will hook 4- and 5- and 6-year-olds on the brand now." A Sesame Street press release says that there's definitely a Richard Belzer muppet and that plot includes detectives finding "things that start with the letter 'M' such as a cow named Murray that makes mmooo sounds." Hmm, Law & Order: Playground Control Team, anyone? And as we did some searching, we found this cool video of "Law & Order: Special Muppets Unit" on YouTube!
And the Muppets Wiki noted when Detective Lennie Briscoe (RIP, Jerry!) mentioned Sesame Street.