Chicken guy cannot be moonsung, he looks bigger than moonsung. And those videos are 5 years old it's impossible he had that big of a frame back then. Since the video had zero views before, I'm guessing these were made by the professional that also happened to teach moonsung.
It’s a Muay Thai technique. Sure it’s used in MMA, but that’s kinda a no-brainer. MMA is everything useful. Calling it an MMA technique is just not right.
As the MC is winning, suddenly, a wild teacher approaches: "Alright guys, break it up. MC, this is a Korean comic. You must get punished for maximum drama."