There he befriends a girl named Samantha, but their friendship is cut short when her abusive father throws her down the stairs, mortally injuring her.

One day, Tom, Paul and BB stop at the house of reclusive harridan Elvira Parker, who threatens them with a shotgun.

After he activates the microchip, Samantha "wakes up", but her mannerisms are completely mechanical, suggesting BB is in control of her body.

When Harry finds the cellar door open and goes downstairs, Samantha attacks him, breaks his wrist and snaps his neck.

Suddenly, Samantha grabs Paul's neck and her face rips apart, revealing a terrifying variant of BB's head.

Wes Craven and Bruce Joel Rubin's original intent for the film was for it to be a science fiction thriller with the primary focus being on the dark love story between Paul and Samantha.

[5] She admitted that Craven was unsure of her capability to play the role, but ultimately cast her, and was "always encouraging... always prodding me in subtle ways.

"[6] Professional mime artist Richmond Shepard taught Swanson all of the robotic movements that her character has in the film.

During filming of one of the studio-demanded scenes where Sam has a nightmare where her father attacks her in her room and she stabs him with a glass vase, there were difficulties on set with the special effects.

"[7] In an interview with Maxim magazine in May 2000, Swanson said that the fake head of Elvira that was decimated by the basketball was stuffed with actual cow brains that the production crew picked up from a butcher shop.

Craven and producer Robert M. Sherman hired Rubin as the screenwriter because they read his script for Jacob's Ladder, which was unproduced at the time.

[9] For the scene chronicling the transplant of BB's microchip into Samantha's brain, Craven called on the advice of retired neurosurgeon William H. Faeth, who has a cameo in the film as a coroner in Sam's hospital room.

His eyes were constructed from two 1950's camera lenses, a garage remote control unit, and a radio antenna taken from a Corvette.

The voice of BB was provided by Charles Fleischer, who appeared in Wes Craven's previous film A Nightmare on Elm Street as a doctor.

Also, according to Swanson in a 1987 interview with Fangoria writer Mark Shapiro, "Craven suggested that I take a look at the movie Starman because what he wanted to do with Deadly Friend was similar in tone to that film."

It was definitely a mainstream, PG film all the way, similar in tone to Real Genius or Short Circuit, but the point was made that Craven could direct something other than double-barreled horror.

"[13] After principal photography was completed, Craven's original version of the film was screened to a test audience mostly consisting of his fanbase.

[15] The executive vice president of Warner Bros. at the time, Mark Canton, had Rubin write six additional gore scenes into his script, each bloodier than the last.

[16] Furthermore, with the additional gore introduced, the film struggled being granted an R rating with the Motion Picture Association of America (MPAA) instead of an X due to the overt violence.

Since re-writes, re-shoots, and post production re-editing heavily changed the original story, Craven and Rubin expressed strong anger and heartbreak at the studio and then virtually disowned the film.

"[5] Swanson commented that she found herself and the other actors caught up in the studio's attempts to strong-arm Craven into making the film more visceral than what was originally intended.

What we're doing is adding to the deaths of a few people, a jump for the beginning, a new closing scene, and two nightmares—that sort of Wes Craven touch.'"

In a 1990 interview with Fangoria journalist Daniel Schweiger, screenwriter Bruce Joel Rubin said this about the ending and why it stayed in the film: "That robot coming out of the girl's head belongs solely to Mark Canton, and you don't tell the president of Warner Bros. that his idea stinks!"

[19][20] In another interview, Rubin told the story about how the $36,000 that he got paid for writing the script for Deadly Friend saved him from going nearly broke due to the four months long Writer's Guild strike and also helped him with a bar mitzvah for his son and to buy a house.

In the same interview, Rubin said how at first, he did not want to write the script, but after changing his mind, he called Robert M. Sherman and got the job.

"[21] Due to all of the gore scenes that were added into the film—as well as Craven's contentious history with the Motion Picture Association of America (MPAA)—it was initially given an X rating.

The mixture of teenagers and terror as seen in the trailer implied that Deadly Friend would be like Craven's A Nightmare on Elm Street.

Hoping to score a financial success with the Halloween trade, Warner Bros. released Deadly Friend in theaters on October 10, 1986, but the film was a box office bomb, grossing $8,988,731 in the United States against an $11 million budget.

AllMovie gave the film a generally negative review, writing, "It's an intriguing combination of elements, but the end result is a schizoid mess", calling Craven's direction "awkward" and opining that it "lacks the intense, sustained atmosphere of his previous horror hits.

In 2021, numerous Twitter users called for Craven's original cut of the film to be released, sharing the hashtag #ReleaseTheCravenCut for both Deadly Friend and Cursed.