[[caption-width-right:300:That's not a proper SlipknotPonytail, young lady!]]
''April Fool's Day'' is a 1986 SlasherMovie directed by Fred Walton, who also directed ''Film/WhenAStrangerCalls'' seven years prior.
Muffy St. John (Deborah Foreman) is rich and she is about to inherit an old house on an island. She decides throw a party to her pals from college in there [[HorrorDoesntSettleForSimpleTuesday on April Fool's Day]]. But weird things soon start to happen, as someone has stored very different kind of April Fool pranks for the guests... [[spoiler: And the subversions. Oh god, the subversions!]]
Got a loose remake in 2008.
!!Examples contained within this book. Gotcha!
* AllWomenAreLustful: Judging by the kitchen conversation, Muffy, Kit and Nikki love lots and lots of sex. Even Nan, the supposedly repressed good girl, got pregnant.
* BookEnds: The jack-in-the-box appears in the opening credits and shows up again in the last scene.
%%* CameraFiend: Chaz.
* CatScare: Skip is scared by a cat before he is attacked.
* CaughtInASnare: Arch when he is in the forest.
* CerebusCallBack: Inverted. The first time the jack-in-the-box is seen it scares Muffy with a lizard head and the second time it's just a clown.
%%* ClosedCircle: The island.
%%* CountryMouse: Hal.
-->'''Kit''': And don't anyone say 'April Fools' again or I'll rip them apart!
-->'''Skip & Arch''': *Cough*april fools*cough*
* DeadlyRotaryFan: Early in the movie one of the party goers gets horribly mutilated by a boat propeller [[spoiler: It turns out to just be part of the prank]]
* DoNotCallMePaul: It's not Harvey, it's Hal.
* TheDogBitesBack: [[spoiler:Nan's little joke at the end, where she pretends to [[SlashedThroat slice Muffy's throat open]]]].
* EvilTwin: [[spoiler: Muffy's "twin sister" Buffy who is really just Muffy. Skip is her twin though and is evil in the original book]].
* [[spoiler: EverybodyLives: One of the small few horror movies to ever use this trope!]]
* ExplosiveCigar: Harvey smokes one amongst the many gags directed at the guests.
* FinalGirl: Nan seems most likely to be this, then gets killed third. Kit then seems to be the FinalGirl [[spoiler: but of course it's subverted when everyone lives]].
* FreudianExcuse: [[spoiler:The jack-in-the-box moment that scared Clara in the flashback could explain her fascination with pranks]].
* FriendlyScheming: [[spoiler: The whole plot.]]
* PeekABooCorpse: Much of the scares are made of findings of corpses and severed heads.
* PortraitPaintingPeephole: Kit and Rob find one in their room, but there is only cat-clock with moving eyes behind it. It later reappears in much less amusing fashion.
* PreppyName: The rich girl's name is ''Muffy St. John''.
* ReallyGetsAround: Nikki. Sleeps with Chaz but is clearly up for sex with Arch later in the weekend, not to mention flirting openly with Hal.
* RedHerring: [[spoiler:Buck ("They did it!")]] and [[spoiler:Muffy's strange behavior after the first night]].
* ReptilesAreAbhorrent: The snake [[spoiler:underneath the booby trap that snares Arch in the woods]].
* TheReveal: [[spoiler:It's all in the movie's name]].
* ScaryJackInTheBox: Muffy was given one when she was a child, as shown in the opening credits.
* SlashersPreferBlondes: Interesting case since all the female victims are blonde, including the FinalGirl while Muffy is brunette. [[spoiler: Of course then subverted when nobody gets killed at all]].
* WinkDing: Not actually a "ding", the sound heard [[spoiler:when the jack in the box winks at the ending]] is a part of the film's music theme.
* WolvesAlwaysHowlAtTheMoon: Subverted. It was Skip, drunk as hell.