8. Boba Fett Is Actually Dead
Now, this theory has already been disproved thanks to The Book of Boba Fett, but it is still a fascinating concept and thus deserves a space on the list.
The Redditor u/Benvincible had firm ideas about the reveal of Boba Fett in season 2 of The Mandalorian. He claimed that the character was not, in fact, the same version of Fett as seen in the original trilogy and that the iconic bounty hunter was still dead in the Sarlaac Pit. The character who came along in the show was instead a standard Clone Trooper with a case of borrowed identity.
Apparently, the evidence for this came from Boba's physical changes. It supposedly explained why he looked so different from how he did in Return of the Jedi and pointed out why his edges had been softened. Benvincible also claimed that the character had no dialogue hinting at more knowledge than a regular Clone Trooper.
Naturally, the canonical reveal of the character escaping the Sarlaac pit - alongside plenty of other holes - caused this theory ship to sink, but it's still a fun idea.