I recently came across this arm wrestler through videos and pictures on the internet. His name is Matthias Schlitte from Germany. It's not stated on his website what exactly is going on with his arm (some say it's a birth defect, some don't), but it's oddly interesting to see the video of the one nicknamed Hellboy, as one arm is much bigger than the other. Check it out!

He unfortunately loses in this video, but it's still neat to watch!