The Thepnossen are a Gamma Quadrant species and a minor member of the Dominion.

Sometime prior to 2376, Eris, the then Sixth Taran'atar and several other Jem'Hadar had viewed a Thepnossen dance. Taran'atar viewed it as foolish and wasteful and described it as such out loud. The Second heard him and reduced him in rank to Seventh. The incident with the Thepnossen taught Taran'atar to be more careful with what he said and who would hear it.

When fighting a Hirogen Alpha in 2376, Taran'atar thought the way they fought other was like a Thepnossen dance. (DS9 - Gateways novel: Demons of Air and Darkness)