The Phased plasma torpedo was a variant of the plasma torpedo that could partially phase through a barrier (like a shield) before exploding. These weapons were never used or tested before 2378, when 20 rounds were given to the USS Sovereign after protecting Starbase 12 from a joint Cardassian/Kessok fleet in the Maelstrom during the Kessok Incident. (TNG video game: Bridge Commander)
- The TNG game Bridge Commander implied that phased plasma torpedo casings could be fired from a normal quantum torpedo tube, because the Sovereign could fire phased plasma torpedoes through either quantum torpedo launcher. However, this assertion has yet to be verified in canon.
The Bouteina refit of the Norexan-class were outfitted with a complement of such torpedoes. Since plasma torpedo launchers, along with their casings, were too bulky to be used practically on Federation ships, Starfleet had to use the smaller casings (F-type according to Romulan shipbuilding conventions because it was the largest, if only, size the Federation could use) to develop these phased plasma torpedoes.
Jem'Hadar battleships had a weakness that was exploitable by shooting phased plasma torpedoes at the antimatter storage system's primary support braces. (Star Trek: The Stoneship Files: "Generational Ghosts")