Tantalus V

Tantalus V was a planet in the Alpha Quadrant. In the 23rd century, it was the location of the Tantalus Penal Colony. (TOS episode: "Dagger of the Mind")

Mirror Universe
In the Mirror Universe, General Shran ordered all outposts on Tantalus V destroyed, claiming the world was a rebel stronghold. In fact, there were no rebels on Tantalus V, and the assault was carried out for propaganda purposes only. (ENT novel: Age of the Empress)