The Phantom vessel generator was a device used in Caius' Tel'tak, which had the ability to create multiple phantom vessels.
After activation, the generator created several phantom vessels and also projected the energy signature of an actual ship to further give them the appearance of real vessels. The purpose of this device is to fool enemies into engaging the phantom ships while the ship that projected them could escape. It is unknown what types of vessels the ship can project, although it is able to at least create four phantom Al'kesh.
In 2005, SG-1 had to recapture Caius' modified Tel'tak as part of a larger bargain. Although the group was successful, they soon faced a large fleet of Lucian Alliance vessels. To escape this fleet Vala Mal Doran activated the phantom vessel generator - one of several modifications made by Caius to his ship - to fool the fleet into thinking that several Al'kesh were decloaking. This allowed SG-1 to escape, although two Lucian Al'kesh followed them. (SG1: "The Ties That Bind")