Inspector Spacetime

Two cosplayers dressed as Constable Reggie and the Inspector from Inspector Spacetime were at San Diego Comic-Con. (COMIC: Selfie)

Behind the scenes
The NBC comedy featured Inspector Spacetime as a show-within-a-show which follows the eponymous Inspector and his Constables as they travel through time and space in their  X-7 Dimensionizer time booth, fighting enemies such as the "Blorgons", armed only with a quantum spanner, an analogue to the sonic screwdriver. A British programme, Inspector Spacetime is said to have begun in 1962, thus making it the oldest sci-fi show on television.

The running gag rose to the level of an online meme, with people ironically pretending to be fans of the show, making up new details and alleging that it coexisted with Doctor Who, which purported Inspector Spacetime fans affected to treat as a contemptible rip-off of Inspector Spacetime. Eventually, a series was created with Travis Richey reprising his role as the Inspector; created without NBC's permission, the series had to drop the Inspector Spacetime name itself and modify the main character's costume, coming out under the title of Untited Web Series About a Space Traveler Who Can Also Travel Through Time. Still a Doctor Who parody in its own right, this series introduced a companion to the Inspector named Piper Tate, in reference to the last names of Billie Piper and Catherine Tate.

The cosplayers in Selfie are actually dressed as Troy and Abed from Community when they cosplayed Constable Reggie and the Inspector from the 1980s "Inspector Spacetime Christmas Special". (The colouring of Constable Reggie's costume is inaccurate.)

Inspector Spacetime was distantly acknowledged by Doctor Who some years before the comics cameo, in the form of the Official Doctor Who Tumblr showcasing a fan-made poster for Inspector Spacetime in 2011 as an example of Doctor Who fanart.