I met two German guys at a bar recently--they were here for a work trip and we started chatting about MMA, submission wrestling, and their training in Judo and Brazilian jiu jitsu. After a few beers we decided to take it back to my place and practice some choke holds and actual submission matches. This is the bigger of the two--he said I'd never be able to choke him out to tap, and that he'd never been put out before. 

The rear naked choke challenge didn't work out so well for this guy. He passed out for the first time ever from a choke hold. Compliments of Krush.