->'''Agatha:''' Yesterday you took out a whole army of [[HumongousMecha war clanks]]!\\
'''Gil:''' That was a ''small army''. This is a ''big spider''!
-->-- ''Webcomic/GirlGenius''

A seemingly invulnerable character reveals that they are deathly afraid of ''X''... therefore, ''X'' is certainly going to be a recurring obstacle, [[KryptoniteIsEverywhere no matter how unlikely]]. The {{Trope Namer|s}} is a line in ''Film/RaidersOfTheLostArk'', reminding us that IndianaJones hates snakes when he discovers that the Well of Souls is crawling with them.

A subset of FatalFlaw. FearOfThunder (also known as brontophobia), SpidersAreScary (arachnophobia), {{Claustrophobia}}, AfraidOfBlood (hemophobia), AfraidOfDoctors (iatrophobia), and AfraidOfNeedles (trypanophobia) are specific sub-tropes of this.

This is common in horror/sci-fi stories dealing with a "master of fear" (such as [[Franchise/ANightmareOnElmStreet Freddy]], [[Literature/{{It}} Pennywise]], or [[Franchise/{{Batman}} the Scarecrow]]), in which the monster [[IKnowWhatYouFear uses his powers to guess his victim's worst fear]], and then use it against him/her to make them a [[CowerPower quivering heap]]. Enemies who know about this weakness are prone to use FlawExploitation and as [[WeHaveWaysOfMakingYouTalk a way of coercing the hero]]. It can also overlap with TheDreaded. If an innocuous object causes fear that renders someone helpless, it may overlap with WeaksauceWeakness.

As you can imagine, TruthInTelevision. Compare PrimalFear for examples where common phobias are gleefully exploited in horror fiction. No personal examples, please. Not to be confused with ReptilesAreAbhorrent, but it helps to explain it some.
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!!Examples
[[index]]
* WhyDidItHaveToBeSnakes/AnimeAndManga
* WhyDidItHaveToBeSnakes/{{Comics}}
* WhyDidItHaveToBeSnakes/FanFics
* WhyDidItHaveToBeSnakes/{{Film}}
* WhyDidItHaveToBeSnakes/{{Literature}}
* WhyDidItHaveToBeSnakes/LiveActionTV
* WhyDidItHaveToBeSnakes/{{Music}}
* WhyDidItHaveToBeSnakes/ProfessionalWrestling
* WhyDidItHaveToBeSnakes/RecordedAndStandUpComedy
* WhyDidItHaveToBeSnakes/TabletopGames
* WhyDidItHaveToBeSnakes/VideoGames
* WhyDidItHaveToBeSnakes/WebAnimation
* WhyDidItHaveToBeSnakes/{{Webcomics}}
* WhyDidItHaveToBeSnakes/WebOriginal
* WhyDidItHaveToBeSnakes/WesternAnimation
* WhyDidItHaveToBeSnakes/RealLife
[[/index]]
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