Creature (These Stolen Hours)
Creatures resembling crabs and which fed on the electrical impulses associated with the perception of time, infested a space station after Professor Artemis Vane created an incision in the space-time continuum leading there. They latched onto the mouths, eyes and noses of the researchers aboard, feeding on them.
The creatures phased in and out of time and were only visible in the dark, being discovered days after their arrival by the Sixth Doctor. He and Artemis, with assistance from Charlotte Pollard and Martin Chesleworth, built a machine which filled the station with chronons, souring their food source and causing them to leave through the incision which was promptly stitched up. (AUDIO: These Stolen Hours)