The slasher as fear factor is one of the most prevalent types of horror movies around, and with good reason: It taps into the most basic fear of being hunted by someone trying to kill you (often for no good reason other than they're nuttier than a squirrel's nest). Here's the 15 of the best, each with their own uniquely morbid appeal. Disclaimer: The definition of a slasher varies, so a few films on this list might not be considered slashers by some people. These movies are listed in descending order, with the best (slashiest?) saved for last.

15 of 15 'I Know What You Did Last Summer' (1997) Matt Champlin/Getty Images Although it tends to fall in the shadow of the other Kevin Williamson-penned '90s slasher, "Scream," "I Know What You Did Last Summer" stands on its own right as an intense, tightly written mystery. High schoolers accidentally run over a man one summer night and instead of exchanging information, they toss the body into the ocean and vow never to speak of it again. Unfortunately for them, a year later, someone dressed as the Gorton's fisherman decides to avenge the hit-and-run.

14 of 15 'Satan's Little Helper' (2004) This darkly comedic little gem has a twisted concept: On Halloween, a 9-year-old boy obsessed with a video game called Satan's Little Helper befriends a serial killer dressed as a devil. The slow-witted kid, thinking that it's all a game, follows the killer around as he dispatches his victims. It's a bit of a one-trick pony, but it rides that pony amazingly well with strong acting and hilarious, irreverent humor.

13 of 15 'Toolbox Murders' (2003) This well-made slasher from legendary director Tobe Hooper ("The Texas Chainsaw Massacre") is a welcome throwback to the '80s slasher heyday. Although it went straight to video, is has the professional quality of a theatrical release — something you can't say often in this era of digital D.I.Y. video. A couple moves into a historic Los Angeles apartment building that houses a dark history — and a ski-masked murderer. The killer uses a variety of tools — hammer, nail gun, drill — to dispatch his victims in a series of nicely staged (and grisly) set pieces.

12 of 15 'Stagefright' (1987) An escaped mental patient torments a group of thespians rehearsing at a theater in this brazen Italian entry. Over-the-top kills, an '80s synth-pop soundtrack, a ridiculously bad play backdrop and a killer wearing a giant owl head highlight this fun, campy film whose lowbrow appeal illustrates the difference between a giallo and a slasher.

11 of 15 'Hatchet' (2007) An unusually sharp sense of humor and delightfully gruesome kills characterize this conscious attempt to return to the '80s slasher mold.

10 of 15 'Alice, Sweet Alice' (1976) This disturbing shocker melds slasher violence and giallo artistry in a tale of a masked, raincoat-clad child murderer who may or may not be a child herself. Alice is blamed for the death of her little sister (played by a very young Brooke Shields), of whom she was insanely jealous, and as she seeks to clear her name, the body count rises, and even the audience isn't sure if she's innocent or not. A stunning, atmospheric whodunit.

09 of 15 'Child's Play' (1988) "Child's Play" isn't often mentioned when it comes to slashers, but it has all the goods: a homicidal maniac (who just happens to be a doll), grisly murders, a high body count and a killer who just. Will. Not. Die. Unlike most slasher villains, Chucky is verbose and fond of wisecracks — like Freddy in "A Nightmare on Elm Street" — although the original "Child's Play" is less comedic than later sequels (again, like "Nightmare").

08 of 15 'A Nightmare on Elm Street' (1984) Despite an amazingly stiff debut from Johnny Depp (and really, the entire cast), this groundbreaking slasher classic delivers an innovative concept, an iconic bad guy (Freddy Krueger) and dreamy special effects that create all-time great images like Tina being dragged across the ceiling of the bedroom, Freddy's glove attacking Nancy in the bathtub, Glen (Depp) getting sucked into his own bed and the infamous "tongue phone." And how many slashers can say they inspired a DJ Jazzy Jeff and the Fresh Prince song?

07 of 15 'Alone in the Dark' (1982) This is an unusual entry: a slasher with multiple, unmasked killers and respected veteran actors like Donald Pleasance, Martin Landau, and Jack Palance. These three add a level of class to a film about four mental patients — a child molester, a deranged war vet, a psycho preacher and someone known only as "The Bleeder" — who escape their asylum and attack the family of a new psychiatrist, whom they mistakenly believe killed their old doctor. (They are crazy, after all.) Scary, fun, well-written and overlooked.

06 of 15 'Evil Dead Trap' (1988) Before the onslaught of ghost stories, Japanese horror was often as graphic and low-brow as American. Exhibit A: "Evil Dead Trap." This is brutal, graphic stuff (Pierced eyeball, anyone?). The plot begins a bit like David Cronenberg's "Videodrome": The hostess of a late-night submit-your-own-video TV show receives a mysterious submission that appears to be a snuff film. She investigates its origin with members of her crew, tracking it back to an abandoned warehouse. There she runs headlong into a trap (some might call it evil) set by a masked killer clad in military gear. He offs them one by one in wonderfully elaborate set pieces (foreshadowing "Saw"). The ending must be seen to be believed ... if not really understood.

05 of 15 'Final Destination' (2000) There might be some debate about whether "Final Destination" is a slasher, but just because the villain isn't human or even visible doesn't mean that he/she/it is any less of an unstoppable killer. The killer in question is Death itself, and it's a tricky, heartless bugger who seeks to claim the lives of the high school French class members who got off a plane before it crashed. Since they had been fated to die on the plane, they broke Death's plan, and now it's got unfinished business, picking off the kids one by one in extravagant, red herring-filled "accidents." It's an ingenious concept and one that's perfectly executed — although diminished somewhat by the derivative sequels.

04 of 15 'Friday the 13th Part VI: Jason Lives' (1986) The pinnacle of the "Friday the 13th" series is wonderfully cartoonish from the get-go, with an opening scene in which Jason is revived by a bolt of lightning that segues into a title sequence that parodies James Bond. "Part VI," which had to come on strong to make up for the betrayal that fans felt from "Part V," infuses a great dark sense of humor without sacrificing the scares or the gore. Although the first seven films in the series are remarkably solid, if you have to see only one "Friday the 13th," make it this one.

03 of 15 'Black Christmas' (1974) A true groundbreaker and one of the first legit slashers, "Black Christmas" predated the more well-known "Halloween" by four years and features a "killer making s crank call from inside the house" concept that predated the original "When a Stranger Calls" by five years. Even to this day, its tale of a maniac terrorizing a sorority house can make your skin crawl — largely because of the über-creepy phone voice (done in part by director Bob Clark himself) that makes you want to shower after hearing it.

02 of 15 'Scream' (1996) Perhaps the ultimate slasher, "Scream" smartly built upon the tradition that its predecessors had established, taking bits from here and there and fusing them with a clever plot, a snappy, self-conscious script that pokes fun at the genre, a masterful director (Wes Craven) and a modern flair. It single-handedly reinvigorated slashers, which had run their course by the end of the '80s, making serial killing once again marketable to teenagers.