10 Worst Betrayals In Horror Movie History 

The runaway success of Wes Craven's post-Freddy horror franchise, Scream, cleansed the palette of an increasingly tired genre. This 'meta-slasher' also has a nasty betrayal of its heroine, a classic Craven final girl.

Sydney Prescott still grieves for her mother, raped and murdered almost a year prior. The cops think they have the killer behind bars but when teen Casey is slain and the bodies begin to pile up, everyone becomes a suspect.

Craven knew the rules of the genre (he helped invent them) and laid them bare for audiences, making Scream feel almost interactive - virgins survived, sex and drugs were a death warrant. Along with that came the killer hiding in plain sight, Syd's boyfriend and Ghost Face himself, Billy Loomis (apologies for the spoiler but it's been 25 years...).

Billy is at first the main suspect - his mobile phone (rare for '96) falls from his pocket right after Sydney receives a threatening call and is attacked. He's arrested and later released, and despite him being really quite creepy, there's just no motive... yet.

Billy finally seduces the cautious Sydney, she trusts him now and that's when he and his accomplice (Matthew Lillard on fine freaky form) reveal themselves as the killers. Seems that Syd's mom was having an affair with Billy's dad, resulting in divorce and one messed up teen.

Reason enough yes, but it's one hell of a betrayal. Loomis keeps his composure for a year whilst plotting his revenge, earning the trust of the emotionally fragile Sydney.