The Beast (Valerie on the Stairs)

In the Masters of Horror segment/short film Valerie on the Stairs, writer Rob Hanisey encounters a mysterious woman named Valerie who pleads with him to save her from a monster called The Beast.

Valerie on the Stairs
Rob moves into Highberger House, a rent-free apartment for developing and struggling writers until their first publication (when they'll be kicked out), following the suicide of a previous tenant. During his time there, Rob is visited by Valerie who asks him to save her from a being that drags her away. The noises he makes while trying to save her repeatedly annoy the other residents, particularly Patricia Dunbar who dislikes him for this. Two other writers Bruce Sweetland and Everett Neely don't mind, however, although Rob continues trying to find out about Valerie.

While on one occasion in Bruce's room, Rob discovers a story penned by Bruce, Patricia, and Neely entitled "Valerie on the Stairs". Bruce becomes hostile towards Rob for this discovery and kicks him out of his apartment. Not long afterwards, Valerie appears to a shocked Bruce and orders the Beast to kill him. The Beast does so by ripping his spine out. Bruce's corpse draws more suspicion from Rob although the others continue to deny the story, particularly after he discovers Neely's poster of a 1950s era film featuring a monster fitting the Beast's appearance (which also reveals Neely's true name as Neil Everett). It is revealed that the three writers collaborated on the text with Everett creating the Beast, Patricia creating Valerie, and Bruce creating the torture-horror scenes. Somehow, the two have come to life and are attacking their creators.

Patricia, intending to leave, is accosted by Valerie in her room. Patricia fawns over Valerie as her love creation to which Valerie questions why she would leave her to be tortured by the Beast. On cue, the Beast rips into Patricia's chest and leaves her to die as the two vanish. Rob and Everett see this, prompting Everett to reveal that the three of them did indeed create the story and its characters. Behind Everett's wall, the path of the Beast's torture chamber is revealed where many girls were dragged away to death. Everett also suspects that Rob is another creation although Rob denies it.

In the chamber, the two are approached by a Rob's ex-girlfriend, who was one of the Beast's victims, who bites into Everett's neck, killing him. Rob then confronts the Beast and seemingly destroys the Beast by knocking him into a fire. However, the victory is short-lived as Rob pulls Valerie to the roof against her will. Valerie, being a fictional character, disappears and indeed, as Everett suspected, Rob discovers he is fictional as well and follows suit, turning into a trail of papers.

Aspects
The Beast was essentially the typical demon who lorded over Valerie and carried women off to their deaths. At some point, The Beast became real alongside Valerie and decided to kill their creators.

Trivia

 * The Beast was played by Tony Todd, the actor known for portraying Candyman.