What popular fan theories were later revealed to be true?

Oftentimes, if a show, book or movie has a mystery, dedicated fans will try to solve it before it's revealed. From How I Met Your Mother to Lost, producers have kept fans guessing until the very end.

One user on Reddit asked what fan theories have turned out to be true, and the answers are truly fascinating. Warning: spoilers ahead.

Many knew the street peddler in Aladdin was more than he seemed:

The Simpsons aired a cliffhanger asking who shot Homer's boss, Mr. Burns, and one person figured it out before anyone else:

Harry Potter fans knew Snape's history before it was revealed in the final book:

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That's not all Harry Potter fans predicted:

The entire concept of How I Met Your Mother was, clearly, who the mother was -- and some figured it out:

Finally, Lost fans had a feeling even the producers did not know what was going on after a while:

Whether we predict endings correctly or not, the fun is in the speculation -- and of course, the eventual reveal.