Wes Craven’s Scream featured a big twist when Billy Loomis and Stu Macher were revealed as the killers behind the Ghostface mask, and while Billy explained his reasons to make Sidney’s life a living nightmare, Stu’s motivations weren’t that clear. The horror genre went through a rough patch in the 1990s after peaking in the 1980s, but not all horror movies from that decade were bad, and one that’s often credited as the movie that revitalized the genre is Scream, directed by Wes Craven and written by Kevin Williamson.
Scream follows Sidney Prescott (Neve Campbell), a high school student who becomes the target of a mysterious masked killer known as Ghostface, who also starts attacking her friends and family. What made Scream stand out was its satirization of clichés of the horror genre and meta-commentary, as well as its many references to other horror movies. Scream arrived with one big twist at the end when the identity of Ghostface was revealed, and as it turns out, there wasn’t one but two killers on the loose, who were very close to Sidney.
In the final act of the movie, Sidney’s boyfriend, Billy Loomis (Skeet Ulrich), is revealed to be the killer but he didn’t act alone. Adding to the twist was the reveal of a second killer: Stu Macher (Matthew Lillard), Billy's friend and the boyfriend of Sidney's best friend. Billy explained that his reason for killing Sidney’s mother, Maureen, was all about revenge, as she had an affair with his father that led to his mother abandoning him, and that was only the beginning of their killing spree. A reason for Stu to join Billy wasn’t revealed, and the only clue to his possible reason was “peer pressure” because he was “sensitive”, but he said that while bleeding out and when questioned by Sidney about what he was going to tell the cops.
Stu, then, has been assumed to have helped Billy kill all those people just for the thrills, and fans have discussed over the years how his over-the-top personality and exaggerated mannerisms were a red flag from the beginning, implying that he wasn’t mentally stable at all and thus was plausible that he was manipulated into helping Billy. Others have pointed out his relationship with Casey Becker (Drew Barrymore) as a motivation to kill, as it’s mentioned that she dumped him for Steve Orth (who they also killed at the beginning of Scream). However, this wouldn’t explain why he helped Billy kill Sidney’s mom. In Scream 3, it’s revealed that Sidney’s half-brother Roman Bridger (Scott Foley) was the actual puppet master, who showed Billy a tape of his father and Maureen together in order to convince him to kill her. Roman also told him to get an accomplice that could be controlled easily so he could blame him for all his crimes if the plan went wrong, and Stu was the one.
Stu’s motivations to kill alongside Billy in Scream will remain a mystery unless Williamson or even Lillard shed some light on it, but perhaps he never needed a reason in the first place, and it was all for the thrills of killing and avenging either Billy or himself. Stu might be part of the list of slashers in horror movies that kill without an apparent motivation (such as Michael Myers in the reboot Halloween trilogy), which would make him a very dangerous character.
