Emperor (The Panic Room)
From Tardis Wiki, the free Doctor Who reference
The Emperor was an imperial ruler on the planet Arabia whose fear led to the construction of a panic room, a safehouse. However the panic room was infiltrated by a panic creature that for years fed off the Emperor’s fear. When the arrival of the TARDIS increased the Emperors fear to a new high the panic creature became fully manifest for a short while before the Doctor, Amy Pond and Rory Williams manage to convince the Emperor that they are holograms and part of the panic rooms defences. They create a chill-out zone which calms the Emperor down and the panic creature is returned to its natural state. (DWA: The Panic Room)