(coexisting on another dimensional plane)
In the mirror universe, Vic Fontaine was a Terran who was killed by Julian Bashir during a firefight on Terok Nor in 2375. The fight was witnessed by Rom and Quark, making them wonder how it was possible for Vic to be an actual person, while he was a hologram in their universe. (DS9: "The Emperor's New Cloak")
Appendices
Appearances
Background information
Like his counterpart, Vic was played by James Darren, who went uncredited for this appearance. Unlike his counterpart, this Vic was not a hologram. It was not specified how this was possible, though - since mirror Fontaine is never actually called "Vic", and is only referred to by his last name - perhaps he was actually the counterpart of Felix, whom the holographic Vic's program was modeled after, similar to how The Doctor was modeled after Dr. Lewis Zimmerman.