Oroborus

The Oroborus was a snake-like creature able to traverse dimensions and feed on time. It could consume chunks of the timeline; the more it ate, the more it grew. It could shed its skin like real snakes. Once it was fully grown it could consume an Earth-sized planet in hours.

The Oroborus made its way to Earth through Alistair Gryffen's Space-Time Manipulator and hid in Gryffen Manor's basement. It consumed time until Starkey discovered what was going on and lured it into the Manipulator's path, sending it away. (K9TV: Oroborus)
 * It is unclear whether there was any relationship between this species and the Oroborous Worm.

Behind the scenes

 * Its name comes from ouroboros, the symbol of the circle of life depicted as a snake eating its own tail.