''Betrayal at House on the Hill'' [[GrammarNazi (and yes, that's the actual title)]] is a unique {{Adventure Board Game|s}} published in 2004 by Creator/AvalonHill. Three to six players take the roles of various character archetypes, such as a {{J|erkJock}}ock, a FinalGirl, a [[MorallyAmbiguousDoctorate Professor]], a FortuneTeller, a [[AmbiguousInnocence seemingly sweet little girl]] or a [[AmbiguousInnocence curious young boy]]... Each miniature has two different 'characters' attached to it, such as the Scientist doubling as a PreacherMan. Whatever their role, the cast find themselves trapped inside a haunted mansion and set out to explore, with players drawing and setting out floor tiles with each new room they enter.

However, sooner or later, somebody's going to trigger the Haunt, revealing the Mansion's terrible secret -- and one of the heroes [[FaceHeelTurn turns on the rest]]. A wide variety of scenarios are included with the game -- players can end up facing {{Giant Spider}}s, [[OurVampiresAreDifferent Vampires]], {{W|olfman}}erewolves and other monsters, or find themselves playing ChessWithDeath, [[IncredibleShrinkingMan suddenly shrinking]], or dealing with the house flooding or collapsing into a UsefulNotes/{{Black Hole|s}}. And since the house is built anew during the exploration phase, every game is a different adventure.

Sadly, the design is a bit clunky in areas. While plastic minis were included to represent the heroes, monsters are represented by paper punch-out counters (probably because of the sheer amount of creatures that can be involved). Upon the Haunt occurring, Heroes and Traitors must split up to quickly read over their booklets on the scenario, which can cause the game to stall out a bit. Worse yet, the game was originally published with a few ''errors'', leading to even more game-stopping confusion and frustration. Betrayal can prove quite fun with the Errata and the various fan-created content floating around. The second edition- published in 2010 by WizardsOfTheCoast- fixed most of the problems as well as adding a number of new haunts.

An expansion titled [[http://avalonhill.wizards.com/games/betrayal-at-house-on-the-hill/widows-walk Widow's Walk]] was released in October 2016.

!! ''Betrayal at House on the Hill'' can contain examples of:

* AlienGeometries: One of the easier ways to explain the Mystic Elevator. Especially if there are secret stairs connecting to it.
** In the first edition, the sunken lake could only be found on the upper levels, never the basement. Sadly, this was fixed in the second edition.
* AlienInvasion: Shows up in at least one haunt.
* AllJustADream: The traitor in the [[spoiler:"Here There Be Dragons"]] scenario thinks they're dreaming, and so isn't worried about killing their friends. They'll just wake up afterward, right? ... right?
* AmbiguousInnocence: That [[ChildrenAreInnocent teddy-bear toting girl]] might turn out to be in league with the minions of hell.
** The "Missy Dubourde" version of the little girl character already vivisects frogs for fun, [[AllThereInTheManual according to the manual]].
* BadassPreacher: In the right scenario, Father Rhinehart is distilled badass.
* BigBad: The player who ends up as the traitor becomes the de facto BigBad.
* BigCreepyCrawlies: One haunt involves giant bugs.
* BlobMonster: One of the several possible scenarios.
* BrainwashedAndCrazy
* CanineCompanion: One of the omens that can be encountered is a stray dog that will follow and obey the hero who finds it. [[spoiler:Subverted if it triggers the Werewolf scenario, as it will instantly ally itself with the Werewolf.]]
* CatsAreMean: [[spoiler:That darn cat during the shrinking scenario almost makes it {{Unwinnable}}.]]
* ChekhovsHobby: Every character has hobbies listed on their character card. Each character is also scripted to be the traitor in certain scenarios, ''because'' of their relevant hobbies.
* ChessWithDeath: A possible scenario involves the characters being challenged to a chess game with Death, gradually killing them each time they lose.
%%* ClosedCircle
* CreepyBasement: The basement is the only floor where certain rooms such as the Catacombs, Crypt and Pentagram Room can be placed. You're also likely to be stuck there, unless you find the stairs or find some other way out by sheer chance.
* CriticalExistenceFailure: No matter how low your stats get during the exploration phase, you'll continue to live so long as the Haunt hasn't been revealed. If it ''is'' revealed, though, and one or more of your stats are at the skull level, you will instantly fall over dead, essentially resulting in this trope.
* DamselInDistress: Some Haunts involve NPC victims that require [[EscortMission protection]].
* DiscOneNuke: Certain items pair ''very'' well with certain heroes if they're lucky enough to encounter them early. Give the Revolver (which allows attacks to be made with Speed instead of Might) to [[MeaningfulName Darren "Flash" Williams]] or the Ring (which does the same with Sanity-- [[FanNickname Sanity PUNCH!]]) to Father Rhinehart and watch the fun.
* TheDragon: In haunts where the traitor is not the BigBad, they're usually the next best thing.
* DwindlingParty: Nearly every variety of the trope can happen unless the Heroes completely stomp the Traitor/achieve their goal quickly. Almost bound to happen in a game where the Traitor wins.
* EldritchAbomination: The GodOfEvil scenario mentioned below, and another scenario featuring some massive tentacled ''thing'' whose limbs extend throughout the house.
* EldritchLocation: The titular house always has a random layout. And, of course, it almost always has the Mystic Elevator.
** The ulterior dimension with the poisonous atmosphere, trees resembling 'tubular horrors', discoloured sky, organ-come-teleporter, and toothy humanoid residents that the House moves to in the "Lost" scenario.
* EvilTwin: One scenario creates doppelgangers of the Heroes, who will kill and replace their counterparts unless killed first. [[spoiler: The "good" ending leaves it ambiguous whether the good counterpart or the evil one killed the other and survived.]]
* FaceHeelTurn: Everyone starts as a good guy, until the Haunt (which nearly always turns one person into a traitor).
* ForTheEvulz: Occasionally, this is the motive given to the Traitor.
* FrankensteinsMonster: One of the several possible scenarios.
* FromBadToWorse: The house is full of creepy omens, hauntings, and ominous rooms. It's even possible to become crippled and teeter on the edge of sanity just by initial exploration, depending on your luck. Then the Betrayal starts...
* FromNobodyToNightmare: The Traitor tends to become this once the Haunt hits.
* GameMod: Lots of fan-created content can be found floating around; one notable example are {{Splat}}s and cards for the Franchise/ScoobyDoo gang.
* GeniusLoci: In at least two scenarios, the House itself is the monster, and the traitor intends to feed the other players to it.
* GiantSpider: One of the several possible scenarios.
* GiantFlyer: Another possible scenario with a giant bird.[[spoiler: Though in this case the bird has picked up the entire mansion and you're fighting over the limited number of parachutes]].
* GodOfEvil: In one of the several possible scenarios, the Traitor will try to summon one of these.
* GoMadFromTheRevelation: More than one Scenario starts with this happening to the Traitor.
* GoThroughMe: Since movement is slowed by hostile characters, and creatures can only attack once per turn, it is possible for a well coordinated team to buy a character a round or two to make a vital roll.
* ImAHumanitarian: "The Feast."
* ImHavingSoulPains: You can be attacked by spiritual damage (Knowledge and Sanity, as opposed to Might and Speed). Also, the background stories of some haunts (such as Dance of Death) refer to your characters having these.
* IncredibleShrinkingMan: One of the several possible scenarios.
* KarmaHoudini: Even if the Traitor loses, there are a few haunts that make no mention about the Traitor receiving any form of punishment.
* KillItWithFire: Certain monsters can only be defeated this way.
* LetsSplitUpGang: A common strategy when the game starts is to have all the players spread out to explore the house as quickly as possible.
* LuckBasedMission: During the exploration phase, you're exploring the house blind and trying to discover as much as possible while collecting items, omens, and dealing with event cards that can help or hinder you. If you're unlucky with dice rolls, or what house tiles you draw, you could potentially find yourself stuck in the basement with low stats when the haunt starts, which brings a whole new level of being luck into play.
* LootDrama: [[InvokedTrope Invoked]] in one particular Haunt, "[[ExactlyWhatItSaysOnTheTin Treasure Hunt]]". It's also one of the few Traitor-less Haunts. Rather, everyone is pitted against each other within a now booby-trapped mansion as they try to be the first to find said treasure.
* MacGuffin: Quite a few Haunts involve these, often as the primary means of defeating the Traitor and whatever thing(s) he or she is allied with.
* MalevolentArchitecture: Tiles such as the Tower and the Collapsed Room can damage the player if they lack the right dice rolls.
* ManEatingPlant: One of the several possible scenarios.
* MaskOfPower: [[GoMadFromTheRevelation Increases Knowledge at the cost of Sanity]]. Since it requires a Sanity roll to put on or take off, [[ClingyMacGuffin it can be hard to remove]].
* TheMole: Half of the scenarios.
* MarsNeedsWomen: Both a male example ([[spoiler:the Mummy]]) and a female ([[spoiler:the Ghost Bride]]).
%%* MoreThanMindControl
* {{Mummy}}: One of the several possible scenarios.
%%* NotHimself
* ObviousBeta: The original version. Thankfully, the second edition is much better in this regard.
* OhCrap: A frequent utterance when the Haunt is revealed and you realize the random map has completely hosed you.
%%* OurDragonsAreDifferent
%%* OurGhostsAreDifferent
* OurWerebeastsAreDifferent: Another scenario has were-rats.
* OurVampiresAreDifferent: One of the several possible scenarios.
* RapidAging: One of the scenarios. The two children are often the sole survivors.
* SanityHasAdvantages: Literally. Rolls on the Sanity stat are often crucial to winning, or to staying alive.
* StatDeath: If any of a character's stats fall below the skull at the bottom of your sliding counter, they'll find themselves dead if the haunt has been revealed.
* StaticRoleExchangeableCharacter: At the start of a given session, the players pick a scenario and are given random predefined characters to role-play. Half-way through the game, a variety of scenario-specific roles (usually including at least one traitor) are semi-randomly assigned to some characters, putting an additional role-play layer on top of that.
* TooDumbToLive: Considering that Knowledge is one of the stats that will cause your character's death if it hits 0, it's possible that your character becomes this.
* UnfinishedBusiness
* {{Unwinnable}}: If the traitor turns out to be the guy who's got all the weapons? Or they have to collect {{MacGuffin}}s and already happen to have them? Yeah, um...
** Add in that before the Errata, some Scenarios had conflicting rules or goals that made winning impossible.
** Also, because the map is mostly random, save for what floor a given tile can be on, and that some scenarios require the heroes to be in a certain room/rooms, it is possible that the traitor and his/her army of demons/plants/etc. could be revealed and/or spawn in such a way that they perfectly block the path the heroes need to take to win. This can be especially bad when combined with the first example.
** Although the Haunts have an inherent balancing factor before appearing (Scale of 0 to 12) it is entirely possible for the Haunt to be revealed on the very first omen, on the very first turn; which can be very bad for the heroes who suddenly find themselves bunched together without enough space to run away from any of the newly spawned monster.
* ViralTransformation: The Vampire and Werewolf haunts have the potential to infect and transform the heroes into more of their own kind.
* {{W|olfman}}erewolves: One of the several possible scenarios.
* WickedWitch: One of the several possible scenarios.
* ZombieApocalypse: One of the several possible scenarios.