Process

The Process was a parasitic life form, a species which resembled a slimy worm or leech but with lamprey-like mouths at each end. It had clawed fins and red-brown skin which turned grey with age. It moved by cartwheeling itself end over end, leaving a slime trail behind. The Seventh Doctor speculated that it was a datavore, a creature which consumed information for food. In the Book of Future Legends, it was known as the Amphisbaena.

The creature trited to get inside the TARDIS, but the Doctor's craft warned Ace and him of the danger it faced. They returned to the ship, which the creature was leeching of power. Before the Doctor could find a way to deal with it, the TARDIS collided with the Time Scaphe. This activated its Banshee Circuits and it reconfigured itself into a multi-dimensional city. The creature, now a hundred times larger and calling itself the Process, enslaved the Time Scaphe crew and made itself ruler of the city. Ace disrupted the Process' timeline. It sought to create a new world, then chose to summon the egg from which it had hatched so it could supervise its own birth. However, Vael, intending to kill the Doctor, accidentally turned the full force of his mind against the egg, incinerating it and preventing the Process and its timeline from coming into being. (NA: Cat's Cradle: Time's Crucible)