* In Literature/TheBible, Delilah asks Samson how to [[BroughtDownToNormal take away]] his SuperStrength. Samson tells her that he can lose his strength if he is bound with new ropes or if his hair is braided, both of which are lies. Delilah tries both of these, and summons Philistines to attack him, [[OneManArmy and fails]]. Then, ''after'' she tries to take away his strength ''twice'' and Philistines showed up to attack him ''both times'', Samson tells her to cut his hair, which works. Memorably pointed out by Creator/OrsonScottCard's character [[Literature/TheTalesOfAlvinMaker Alvin Maker]].
** Then again, Samson is established as [[DumbMuscle not the sharpest knife in the drawer]] to begin with. Notice that his thoughts even the morning after his hair was cut were "Philistines? Time to whip their butts again! Wait, why am I so weak... [[EyeScream OW! MY EYES]]!!"
** Abraham is traveling through Egypt with his [[WorldsMostBeautifulWoman lovely wife, Sarah]] in tow. He fears that the Egyptians would [[MurderTheHypotenuse kill him and take her away]] because of her beauty. So, what does he do? He stuffs her [[GirlInABox into a box]]. He didn't stop to think that ''maybe, just maybe'' that box would, you know, have to pass through customs. Then when she is discovered, he tells them that [[SheIsNotMyGirlfriend she's only his sister]], which results in Sarah being taken into the Pharaoh's harem. The ''real'' icing on the cake? This happens [[AesopAmnesia twice!]]
** And then the *exact* same thing happens to his son Isaac![[note]]In fairness to Isaac, "Hey, did I ever tell you about the two times I almost got your mom raped by the king?" is among the more unlikely things for a father to say to his son.[[/note]]
* Probably not the only case in GreekMythology, but the biggest: Rhea fooled her husband Kronos from devouring little baby Zeus by giving him a stone in diapers. To be fair, she did get him drunk first.
** Another notable moment is in ([[ContinuitySnarl one version of]]) the myth of Heracles and the centaurs; when Chiron--Heracles' tutor and one of only two good and wise centaurs--is accidentally killed by one of Heracles' poisoned arrows, Pholus--the other good and wise centaur--picks up the arrowhead (in a moment of uncharacteristic foolishness) to marvel at its ability to kill so great and strong a one as Chiron, gets cut on it, and dies from the poison soon after.
* In NorseMythology, Frigg went on a pilgrimage throughout the world and extracted a promise from ''everything in existence'' that they would not harm her beloved son Balder. The other gods even made a game out of it, putting the amused Balder in the middle of a circle and throwing things at him just to watch the things dodge him. That's not the IdiotBall; that's cute. The IdiotBall shows up when Loki disguises himself as an old woman who manages to get Frigg to explain that she didn't get this promise from one thing - mistletoe, because she deemed it "too young" to be bound to such a vow. He immediately gets mistletoe and tricks Balder's blind brother into throwing it at him, resulting in Balder's death. Frigg, you twit, why would you tell ''anyone'' about that, especially knowing that there's a nasty trickster god running around who's really good at disguises?
** ''Any'' time ''anyone'' listens to Loki immediately gets the IdiotBall. It's somewhat justified in that he's the god of lies and it's in his power to convince people.
*** It's also justified in that in some myths, he's on their side -- before he really goes bad, he's a bastard, but he's ''their'' bastard. He does manage to get back Thor's hammer after it's stolen by giants, for instance.