There were A LOT of bad endings here, but I think one clear winner:
Yay! Adam, let's talk about your totally awesome prize and such. You definitely earned it.
Let me take a moment to explain my choice, since I think it sheds a light on what readers might expect from an ending. In reading all the entries (which were pretty dang horrible), certain themes came up that made an ending bad:
1. Too unexpected
Kiersten's Star Wars one is not only unexpected, but nasty. No one would ever buy that as the end (hopefully). Carrie's devastating end for Little Women is also pretty freaking ridiculous, hehe. When something comes out of left field, people just aren't satisfied. That's not to say twists are bad, but that they at least have to be LOGICAL.
2. Negates the entire purpose of the story
Jen had a great example here with Harry Potter waking up from a dream—lame! Getting invested in 700 pages to find out the whole thing was a trippy dream sucks. Nick also had a classic one with Gandalf making Frodo and Sam go to Mordor for nothing. Can you imagine? We got invested for what?
3. No actual resolution
Carrie's Rumplestiltsken falls here—he changes his name to Michael Jackson! Ah! That opens up a whole new can of worms. And H-Duck brought up that terrible scenario where the poor dwarf is flung into a portal never to be heard from again. What the crap? That's it?
4. Goes against "the genre"
Like it or not, genres have formulas. Uh, that's what makes them genres. If you're reading romance, you're expecting somewhat of a happy ending where the couple gets together. Renee's devastating end to Elizabeth and Mr. Darcy would have enraged women everywhere! And as completely hilarious as Jessie's ending to Twlight is, talk about a downer! Carrie's violent end to a children's book also kinda breaks that genre expectation.
Well, Adam's awful ending had it all. It was completely unexpected, it negated the entire purpose of the book, it didn't provide an actual resolution since three dudes were now fighting over the ring, AND it went against the genre (in fantasy usually the good guys prevail, bad guys win here). To add on top of all that, he introduced NEW characters in the last scene! The horror! AND he swore in a book I'm pretty sure has none of the sort. Talk about BAD. So congrats, Adam. You can write one terrible ending.