Brunt the Ferengi, and Weyoun the Vorta were two important recurring characters in Star Trek: Deep Space 9, played by the same actor Jeffery Combs.
They never met onscreen during the run of the TV show. Both characters appeared in one episode, but they didn't meet.
A lot of people have thought this was a missed opportunity, and they should have been an episode where they met.
Were there any EU comics/ novels/ other where they did meet, and have some plot-significant interaction?