Reaper

Reapers appeared in the Ninth Doctor episode Father's Day. They are not named in the episode, but they are referred to as Reapers on official sites.

Reapers are multi-limbed, flying reptiles similar to pterosaurs. They have a sleek head, four long hooked arms and a mouth on their chest. Like the Hunters, the Reapers will search out disturbances in time, such as paradoxes. They then leave the Time Vortex and sterilize the area by devouring everything, with older objects being the tastiest. They engulf creature in a flash of light with their mouth, leaving no traces. Despite these powers, they are material creatures (at least they are in this world), and can be blocked. They can’t pass through solid objects, with older objects being more effective. Unfortunately, the damages from paradoxes are accumulated, so they can be summoned inside these barriers.

The Reapers are similar in both appearance and habitat to the Vortisaurs from Storm Warning, the Hunters from The Pit and the Chronovores from The Time Monster and No Future.