Graske

The Graske are a race of humanoids from Griffoth. The Graske are small humanoids with pebbly brown skin and three tentacle-like feature on their head.

The Graske are a race of conquerers, though unlike other species they do not take a planet by force. Instead, the Graske replace the inhabitants of the planet with changelings. This process is quick, with the Graske replacing the individual with the changeling in seconds. The originals are then stored on Griffoth in stasis chambers in order to maintain the copy. The changeling can be identified by its glowing green eyes.

The Graske attempted an invasion of Earth, stealing people from various Christmases from across time, which was stopped by the Doctor and one of his companions. (DW: Attack of the Graske)

A Graske was hired by The Trickster to capture Maria Jackson. It suceeded, but she escaped. The Graske got her again, but got sent to capture Alan Jackson. Alan fought the Graske and beat it, forcing it to tell him where his daughter went. (SJA: Whatever Happened to Sarah Jane?)