It's one thing I think DS9 always did, fleshing out the universe with weird and wonderful aliens who you (unfortunatley) never got to see. One of the benefits of being a station, the sheer varitey that passes through the airlocks.
There was also the episode where (in conversation) there was a two-headed alien who could never make up his/their mind (think it might have been the one where Odo and Curson bonded).
Ok, so no Betelgeusian Vilix'pran. Just something else, even more interesting.
Commander Austin Harris, First Officer, Deep Space Nine (by FltCpt. Bossco)
8.01 - Darkest Before Dawn
(Chapter 8 added, 12/09/2015)