Wat Dabney is a minor character in Terry Gilliam's first non-Python movie, Jabberwocky.
The protagonist, Dennis (Michael Palin) goes to the city to make his fortune as a cooper. One of the first people he meets there is a legendary cooper named Wat Dabney ("the inventor of the inverted firkin") who's been reduced to begging because he's not a member of the guild that controls the trade.
I first adopted the name on IMDb, back in the late 90s, but retired it when IMDb shut down their general interest forums, and didn't use it on Reddit. I revived it for Lemmy.