The Vore were a species that originated from the Shoal.
Biology
The Vore were large insects, with mandibles and legs sharp enough and powerful enough to tunnel through rock. They had large, bulbous bodies and tiny heads. Their bodies were asymmetrical, with silver carapaces and black hairs protruding through the gaps. They stood on their hind legs and were roughly the size of a human male; their two front pairs of legs were shorter, and all of their legs were moulded into vicious spikes, sharpened curves, and hooks.
The Vore fed on temporal cicatrixes, scars where space-time had tried and failed to heal itself. They could move through the fifth dimension by manipulating hyperspace corridors.
The Vore communicated using gestures and chemical signals. They had no individual intelligence and acted on instinct and transformed the life of planets they invade into chyme (vomit), which they used to grow the fungus on which they fed. (PROSE: The Gallifrey Chronicles)
History
Marnal was the first Time Lord to make contact with the Vore, when he and two other Time Lords visited the Shoal to destroy a temporal anomaly.
In the "first draft" of history, the Vore evolved to become an advanced, benevolent race. However, after Marnal's destruction of the cicatrix on the Shoal, history was "redrafted" and the Vore became a swarming and aggressive force. At date index 309456/4756.7RE/1213GRT/100447TL, the Matrix predicted that the Vore were a possible Last Contact, and a possible final stand between the Time Lords and the Vore would result in the fatalities of 20-40% of the Time Lord population; as a result, the Supreme Council mandated that no Time Lord was to engage the Vore or come within one parsec or one century of any of their moons. (PROSE: The Gallifrey Chronicles)