Shogun/Hendo 2 has to be up there IMO.
Shogun was beating him pretty soundly. Hendo did get a knockdown in the first round but overall, Shogun was pushing that fight, landing all the significant strikes, dropped Hendo twice, if I remember correctly.
Then out of nowhere, boom, down goes Shogun and Hendo hammers on him and the fight gets stopped. The reason I'd say it's a 'dramatic' comeback is because it was Shogun. He was winning that fight, looking rather impressive in doing so, and seeing Shogun lose is always a sad thing IMO.
The reaction from all of the Shogun fans (myself included) is what makes it seem more dramatic, at least for us Shogun fans, you know?
It really sucked to see. Shogun was doing so well. Looked like his boxing did improve after working with Freddie Roach, he showed a better jab than he ever did, controlled the distance well, dropped Henderson a few times, he was doing so damn good and then out of nowhere his nose gets smacked to the other side of his head.
Was a sad moment. But not nearly as saddening as Shogun's loss to OSP. I say that because just a few years ago, Shogun would've beheaded the guy in the first round round. It sucks to see Shogun lose at all, especially when Shogun was damn near unbeatable at one point and would've smashed some of these guys badly but now he's just so far past his prime.
Another one may be Chris Leben's triangle choke win over the sexiest man alive. Leben was losing that fight pretty handily and then out of nowhere he slaps that triangle on in the last round.
Can't forget Lesnar's comeback against Carwin in the same night as well after taking a horrific beating.
And lastly, Anderson Silva's 5th round triangle choke win over Chael Sonnen. It wasn't just dramatic because Anderson got beat down for 4 1/2 rounds and then out of nowhere wins, but all that trash talk from Chael, the way Chael backed it up.. then Anderson just crushes his dreams with what.. 2 minutes left? just crazy.