The Infinite was a spaceship forged during the Dark Times.
History
It was said the Infinite was powered by an Old One and whoever found it would be granted their heart's desire. The Infinite crashed on the asteroid, 7574B, of the Caris System. Its parts were scattered throughout the universe and power contained within faded away. Four data chips were needed to find its secret location.
At some time in the 40th century, these four chips were found by Captain Kaliko, Ulysees Meregrass, Gurney and Baltazar. Baltazar murdered the chips' carriers to get to the ship. He also used the Doctor and Martha Jones to get the location and hijacked the TARDIS to get there. The vessel did indeed have the ability to show people their heart's desire: it provided Martha with a romantic image of the Doctor, and untold riches for Baltazar, but the Doctor prevented the vessel from showing his heart's desire. The Doctor destroyed the vessel. (DW: The Infinite Quest)