Muscle-ups are no easy feat, and this video is a great example of why using the right equipment is so important. The muscle-up is a rare beast – an upper-body exercise that requires both pulling and pushing power and phenomenal core strength to boot. I have looked for the weighted muscle up world record but I'm not sure what it is. It's an unparalleled assault to the upper body, and you have to be strong just to do one. Ask 100 random people in public. The muscle up is one of the most impressive moves in calisthenics and requires a delicate balance of power, strength and technical skill to master.
Most people can certainly not do a muscle up. So here are some of the best examples I have found on Youtube, feel free to share more impressive heavy muscle ups in the comments.

I'd be shocked if you even found 10 people that could perform one with proper form. Those unfamiliar with the move say it's just a pull-up combined with a dip, but a muscle-up is much more than that. Most impressive weighted muscle ups. It’s an exercise engages the whole upper body in a way few other exercises does. A muscle up is an impressive display of strength, coordination and explosiveness that even very fit people may have a hard time accomplishing with practice. They are absolutely an impressive … Not only does a fully-fledged muscle up look jaw droppingly impressive, but they are also a fantastic way to develop elite level upper body strength.