At an event called Dream 13 on March 22, 2010, Josh Barnett delivers an accidental kick to Mighty Mo’s groin. Then, in what might be one of the greatest signs of sportsmanship ever, Barnett allows Mo to kick him in the groin in return. A completely open, unopposed kick. Mo opts for a knee to the groin instead, and the two hug it out.
The first kick happens at around the 2:53 mark. Mo’s return knee happens at about 6:20.