- Star Trek: The Motion Picture
- Star Trek II: The Wrath of Khan
- Star Trek III: The Search for Spock
- Star Trek IV: The Voyage Home
- Star Trek V: The Final Frontier
- Star Trek VI: The Undiscovered Country
- Star Trek Generations
A Romulan warbird, the Decius was created by the entity, Barash, on Stardate 44286.5. Barash used the ship as part of an engineered reality, one intended to keep Commander Riker on the planet Alpha Onias III.
The Decius, commanded by an Ambassador Tomalak, rendezvoused with the Galaxy-class U.S.S. Enterprise-D, with this reality's flagship commanded by Captain Riker. The Decius delivered Admiral Picard and Counselor Troi to Enterprise.