22. Paul Kelly Uses Glove Touch to Blindside Cerrone
In MMA, one of the dirtiest moves is punching (or kicking, and we'll get to that) your opponent just before, during or after the touch of gloves, which is the fight game's signature display of sportsmanship.
Paul Kelly provides a decent example here, though it might only have succeeded in angering Donald Cerrone, who went on to get the submission win. Kelly later apologized for his underhandedness.
You almost have to try to get video quality this awful, but it does show it. Fast forward to about the 1:15 mark.