Edit 2: Anderson Silva gives a great nominee here when he gets KOed against Chris Weidman while trying to bait him in:
Edit: You are really going to like this thread. I know not EVERY GIF fits the thread exactly, but it is a collection of awesome GIFs so enjoy! Here is one of the best, Dave Gardner saying "Hello Japan" then getting a rear naked choke:
Everyone loves a spinning backfist KO or a flying knee KO, but it could just as easily backfire. What are your "risky strikes gone wrong"? It could be a failed attempt at a strike, or a strike that totally backfires on the fighter as well. No celebration GIFs.
All of MMA, not just UFC. Here are some of mine:
UFC 148 Chael Sonnen fails on the spinning backfist in one of the biggest UFC fights ever.
Fedor KOs Arlovski when Arlovski goes for the flying knee
Urijah Faber loses his title in embarrassing fashion to Mike Thomas Brown by failing on his elbow and getting TKOed.
And last but not least, Matt Riddle goes for a flying knee and gets lit up:
Post yours, and which one you think is the worst. I think the Silva one is the worst.