Mountaintop Motel Massacre^{[lower-roman 1]} is a 1983^[1] American psychological slasher film written and directed by Jim McCullough Sr. and starring Anna Chappell, Bill Thurman, and Amy Hill.^[4] The plot concerns a psychotic elderly woman who, after being freed from incarceration, returns to the motel she ran and begins murdering the guests.

Filmed in 1982 in Shreveport, Louisiana, the film was first independently released in the southern United States under the title Mountaintop Motel. In 1985, New World Pictures acquired theatrical distribution rights, and its ending was reshot to feature additional onscreen gore. New World Pictures released the film theatrically as Mountaintop Motel Massacre in March 1986.^[5] Although the film received negative critical reception upon its theatrical release, it has, in later years, been noted for its offbeat atmosphere, and has been referred to as an "early 1980s drive-in gem."^[6]

In rural Louisiana in 1981, Evelyn, who has recently been released from a psychiatric institution, finds her daughter Lorie practicing witchcraft in their basement. This causes her to have a mental breakdown, and she stabs Lorie to death. She convinces the authorities that she had nothing to do with her daughter's death, though suspicion looms over her. Adjacent to her home is the Mountaintop Motel, a group of outdoor cabins that Evelyn rented out as motel rooms prior to her institutionalization.

One morning, Reverend Bill McWiley arrives at the property and rents one of the rooms. Shortly after, a man named Robin Crewshaw arrives and also takes a room; the two men converse about the rundown state of the cabins and share a drink. Meanwhile, newlyweds Vernon and Mary pass through on a road trip and rent a cabin. At nightfall on the nearby highway, cousins Prissy and Tanya have their car breakdown en route to Nashville and are picked up by Al, a lascivious man who pretends to be a record producer in hopes of bedding both of the women. They also arrive at the motel, finding driving conditions unsafe due to a torrential rainstorm.

Mary is getting ready for bed in the bathroom when Vernon is bitten by a snake that Evelyn planted in the room. Mary attempts to use the phone, but it does not work. She rushes outside to the front office. Al, who is coming out of the front office, offers to use his car phone to call the police for the couple, hoping to get an ambulance. Meanwhile, the various guests have trouble sleeping in their rooms: Reverend McWiley, passed out from drinking, is awoken by rats crawling on his bed, and Crewshaw awakens to cockroaches crawling on his body. Back in her room, Mary nurses Vernon, who grows progressively ill.

Meanwhile, Al attempts to initiate sex with Tanya and Prissy, but the girls lock themselves in the bathroom and argue over his claims of being a record producer. Tanya tells Prissy she is willing to sleep with him if it will result in a record deal, and she begins to have sex with Al while Prissy remains in the bathroom. Evelyn enters the bathroom through a trapdoor in the floor connected to a network of tunnels and slashes Prissy's throat with a sickle. Startled by the noise, Tanya opens the bathroom door and finds the room covered in blood, but Prissy is gone. Al notifies Mary and Crewshaw of Prissy's disappearance. Crenshaw notifies the Reverend, who tells Crenshaw he is going to get ready and then come to Crenshaw's cabin. Before he can do that, Evelyn stabs the sickle through his chest. Crewshaw inadvertently uncovers the trapdoor in the bathroom; with Al, they attempt to locate Evelyn but find her absent from the main office. Meanwhile, Evelyn breaches Mary and Vernon's room; with the sickle, she impales Mary through the face and then slashes Vernon's throat as he lies helplessly in the bed. Al and Crewshaw hear the commotion outside and find the bodies in the room while Evelyn retreats into the tunnels via a trapdoor.

Al and Crewshaw descend into the tunnels below while Tanya locks herself inside the car. Crewshaw is attacked by Evelyn, who chops off his hand before slashing his throat. Meanwhile, a sheriff finally arrives at the motel from Al's earlier call, and Tanya informs him of the murders. The sheriff descends into the tunnels and discovers the Reverend's body. He is confronted by Evelyn, who attacks him in a manic state; she attempts to wrest the sickle from a wooden post where it is hanging but dislodges a beam holding the ceiling; it collapses, and the sickle hurls at Evelyn's throat, killing her.

At dawn, Al and Tanya leave with the sheriff in his car. As they drive out of the property, an apparition of Evelyn's daughter Lorie observes them from the woods. As they pull onto the main road, the vacancy sign lights up.

• List of horror films of 1983