The Fendahl Predator was a creature that evolved on the time-accelerated Planet 5 to feed on the Fendahl themselves.
They were a living absence which insinuates itself into subatomic quantum interactions thus collapsing the alternate probabilities by the act of its observation and feeds upon the energies that are released. This makes them Memeovores, creatures that devoured concept itself and were capable of encompassing all of time and space.
A faction of Time Lords used a herd of TARDISes to break the time barrier around the Fifth Planet in order to free the Fendahl Predator for use against the Enemy. (PROSE: The Taking of Planet 5)