- Not to be confused with the documentary I Was a Doctor Who Monster!
A man has been on a pub crawl. When he goes outside for a cigarette, a young woman approaches him. She bites him on the neck and drinks his blood. She hears a noise, and has to leave before she can kill him.
When the man wakes next day, he realises that he has changed. He now has a hunger for blood, but tries not to give in to it. He stays inside during the day and hangs out in bars at night. He notices that he no longer has a reflection, but it turns out he can be photographed.
Twelve days later, he is standing outside a bar and screams in frustration. A man walking nearby calls him a freak. This angers him, and he kills the man and drinks his blood.
Now that he has started, he continues to kill. He puts pictures of his victims on his wall. The press dubs him the "Capricorn Killer" because he has a goatee.
He starts to crave fame as much as he craves blood. One night in a crowded pub he dances with a television drama star. He kills her and escapes in the confusion. Back at home he takes down the pictures of his victims.
One night he sees a beautiful woman in the bar. She tells him to come with her. She introduces herself as Romana. She takes him to her friend, whom she calls Doctor. He is holding a walking stick. He explains to the Capricorn Killer that something brought him into this world and they can only help him one way. The Doctor plunges the stick through the Capricorn Killer's heart, killing him.
- The Capricorn Killer Googles himself.
- The stories in Short Trips: Zodiac are inspired by the signs of the zodiac. This story's theme is Capricorn.
- This story is told with flashbacks and first-person narrative, and includes a fictional book excerpt and television script.
- This story was reprinted in Short Trips: Re:Collections.