Sherlock supplies the “Lock” in the Tumblr fandom crossover SuperWhoLock.
The name combines Supernatural, Doctor Who, and Sherlock, three television series with unusually active online fan communities in the early 2010s. The crossover was not an official BBC, CW, or BBC America production; it was a fan-created blend built through fan fiction, art, GIFs, cosplay, and discussion.
Sherlock refers specifically to the BBC mystery series starring Benedict Cumberbatch as Sherlock Holmes and Martin Freeman as Dr John Watson. That makes “Sherlock” the canonical answer, rather than another British detective programme such as Luther, Broadchurch, or Endeavour.
SuperWhoLock became especially associated with GIF fics: short narratives assembled from animated GIFs featuring characters from all three shows. Researchers have identified a SuperWhoLock GIF fic dating to December 30, 2011, while a fan-made trailer helped the crossover spread more widely in 2012. Its popularity declined by the mid-2010s.