Darkness (Made You Look)
From Tardis Wiki, the free Doctor Who reference
The Darkness was a being who killed people the third time they saw him. He wiped out all of Talmouth bar Mrs Rhodes, who was blind, and attempted to kill Gwen Cooper. He made her hallucinate and managed to summon Rhys Williams, after which he began to drop the illusions without telling Gwen who he was. (AUDIO: Made You Look)
