Doctor Who: The Forgotten
DanC for Es'Cartrss
An evil parasite that took on the form of the Tenth Doctor, the big villain of the story. He tries to fool the Doctor by claiming he's his Meta-Crisis incarnation as well as the Valeyard, while he is none of these.
"Exactly, my dear Doctor. And we do so love our archetypes, don't we? The last Gallifreyan Matrix in existence - and it's all for you." (Pause) "Well, when I say you - I really mean us."
"You should have left me on The Crucible, Doctor. You should have left me to burn with the Daleks. Because you're in MY world now - And I want you to regenerate so that I can take your remaining lives! Only one of us survives this time!"
"Are you sure, Doctor? Maybe I'm a future version of you, wanting your regenerations! Maybe the you that was sent across with Rose came back through time...and calls himself...THE VALEYARD!"
Love this. It comes close enough to Tennant to make you believe it's him, but he sounds different enough to know it's not the Doctor.