High yield energy weapons
The ship seems to be not much smaller than Daedalus-class ships. It possesses green colored high yield energy weapons capable of depleting Starbase Atlantis's shield, though it is not known if they are anymore effective than Wraith weapons. The shots from the weapons have a unique design: they do not look like the pulses released from all other known energy weapons, rather, they emit what appears to be flaming blast. Little is known about its defensive capabilities except it can survive 3 hits from quantum phasers fired from a badly damaged, alternate reality Daedalus, though it will lose weapons capabilities and be crippled. Since the Daedalus arrived after the alien ship was already in orbit in a combat situation, it is unknown how depleted the shield was in the first place. However, the quantum phasers plasma beam is highly effective against this advanced mothership, and a fully powered Daedalus would probably be far superior in a ship to ship fight.
This alien ship can carry a large group of fighters. The hanger is also protected by a green energy shield. The rest of the ship's systems are unknown. (SGA: "The Daedalus Variations")
The ship was encountered in an alternate reality when the First Atlantis Reconnaissance Team were stranded on board an alternate Daedalus, jumping through realities. The ship was found firing at the Starbase Atlantis of that reality leading Sheppard to decide to fire back with the Daedalus' Asgard weaponry. Although the ships weapons were destroyed, it launched several alien fighters. Before the Daedalus was too badly damaged, the drive engaged and it was sent to another reality.
Soon after, as AR-1 was returning through realities the Daedalus was attacked by these fighters again. With the help of the alternate Sheppard, who was piloting an F-302 fighter-interceptor sent from the alternate Starbase Atlantis, the Daedalus was able to destroy the fighters.
Neither the ship nor the alien race who used it have ever been encountered in the normal timeline/universe. (SGA: "The Daedalus Variations")