Changeling
From Tardis Wiki, the free Doctor Who reference
The Changelings are Aliens controlled by the Graske that mimick a lifeform and send the real person to Griffoth. They appear exactly like the original, but their eyes flash a greeny-gold colour occasionly. (DW: Attack of the Graske) There may also be Raxacoricofallapatorian and Zygon Changelings.
