Steamroller Man
From Tardis Wiki, the free Doctor Who reference
Steamroller Man was a man that the haunting the Dead Man, and Helen Towers could sense. Hannah Bartholemew couldn't see him, whereas the Fifth Doctor and Nyssa could. It came from one of Sandra Jane Rimdelle's childhood books. It was designed to delete code and bugs from the system, but then started to delete people. (AUDIO: Masquerade)