This video was created by our boys at Phuket Top Team (they've provided us tons of content over the years) and it features a brilliant take down to heel hook submission by 155lb'er, Ian Entwistle (8-1) from two nights ago UK's Cage Warrior FC 62 (Newcastle).
This is pretty much something out Rey Mysterio's playbook. We just don't see technique like this in professional MMA these days (long gone are the days of Saku and Genki Sudo). Looking at the takedown, I can see where the "drop down" part comes from. Not sure about the "triangle" of it all. What I think I'm seeing is a tricky sacrifice take down born out of a killer forward roll.
Advice: Proceed straight to around 6:20 in the video for the meat & potatoes.