Bait and switches in comics have been around almost as long as the medium has existed. Older comics often had extreme or bizarre covers that would draw a reader in, but whether or not any part of what was depicted on the cover actually would show up in the story was a toss up.
As time has passed the fake outs have only gotten more obvious. Countless covers feature one hero clutching the apparently dead body of another hero, only for the inside story to have all been a dream, or a fake death, or the death of a character that just looks like the hero in question.
DC and Marvel will profit by advertising exciting new events like an upcoming wedding, a character death, or a new superhero - but it doesn't always pay off for the reader. Sometimes the fake out is unintentional, and the writers truly wanted the plot to go one way, but an executive decision was made to change the story. Other times, a bait and switch is used to try and create a twist that won't be as expected.
There's a fine line between implying one story in order to surprise the reader with something else, and just disappointing everyone.
10. Doctor Doom Wields Mjolnir - But Really He Doesn't
This two part Fantastic Four story initially appears to be about Doctor Doom wielding Mjolnir. The cover of issue #536 shows Doctor Doom's hand wrapped around the hammer's handle beginning to lift it up. Issue #537 shows him righteously holding it aloft.
Naturally, this raised some huge interest. Doctor Doom is a villain, but a villain known for living by a strict code of honour. He doesn't fight an opponent if it isn't a fair fight, he'll rescue those he's indebted to, and he always keeps his word.
Doctor Doom is a bad guy, but he's a bad guy who genuinely believes that if he was the ultimate ruler he could bring peace and create a utopia for humanity, which means there was a chance that this cover wasn't a ruse.
Fans were curious to see what circumstances could lead the complex character of being worthy of lifting Mjolnir. Turns out, despite the cover's depiction, he doesn't. While Doctor Doom believes that he will be worthy of lifting the hammer, he simply can't.