Not exactly a horror short in the purest sense this one, but it fits perfectly in our Horror Short banner and has a runtime under 25 minutes, so …
Mirror, Mirror is an episode of the anthology TV series Amazing Stories from the 1980s, created by Steven Spielberg. The episode follows the horror writer Jordan Manmouth who claims he is immune to being frightened by the nightmarish creatures he creates. From being a douchebag he gets reduced to a person with crippling fear when he is stalked by a black-caped phantom through mirrors and everything that gives reflections.
This episode is directed by Martin Scorsese and will give everyone with eisoptrophobia a harder time to stand in front of the mirror while brushing their teeth.
Director: Martin Scorsese
Writers: Joseph Minion, Steven Spielberg
Country & year: USA, 1986
Actors: Sam Waterston, Helen Shaver, Dick Cavett, Tim Robbins
IMDb: www.imdb.com/title/tt0511104/