(covers information from several alternate timelines)
The Dauntless class was a type of starship used by Species 116 during the 2370s. It employed quantum slipstream technology, which allowed it to go higher than the standard Starfleet warp scale. Although created by alien technology, the ship was modified to resemble Federation starships on the interior and exterior by the means of particle synthesis.
The Dauntless was equipped with a quantum slipstream drive allowing it to travel 60,000 light years in three months and was capable of traveling over fifteen light years in only a short time, which otherwise took Voyager two days to cover at high warp.
Arturis nearly managed to trick them into believing that the ship was an advanced prototype sent by Starfleet to retrieve them from the Delta Quadrant. The ship was actually a part of Arturis' plan to take revenge on Voyager and its crew, whom he blamed for the assimilation of his species. He hoped to lure the crew of Voyager onto the ship and then send it into Borg space where they would also be assimilated. His plan failed and the ship was lost to the Borg with only Arturis on it upon entering Borg space. (VOY: "Hope and Fear")
In an alternate timeline, the Federation appeared to have adopted this design by the 26th century, with at least one Dauntless-class starship participating in the pivotal Battle of Procyon V. (ENT: "Azati Prime")
Ships of this class Edit
Though not originally a Starfleet design, ships matching the configuration of the Dauntless appear in the 25th-century timeline of Star Trek Online as the Dauntless-class "Experimental Science Vessel", featuring a special device that mimics the effects of particle synthesis to distract enemies and confuse their targeting.