Guillotine choke, also known as “Front Rear Choke” is very powerful choke in Brazilian Jiu Jitsu. There are many variations of Guillotine choke, but one that Gordon Ryan Pulled on Keenan Cornelius few days a go on ADCC 2017 is really spectacular.
If you’re interested in how he did it check breakdown video from ZombieproofBJJ.