The Kimura

It's a judo move: reverse ude-garami arm lock, which is often called the "Kimura" in BJJ. The name comes from Masahiko Kimura a japanese judoka.
The movement shows similarity with the omoplata, it targets the shoulder joints primarily.
The technique applies on the arm. Same side hand catches the wrist, the other wraps around the opponent's arm and catches your own wrist.
You should point with his arm to the top of his head.

It can be effectively use even to just sweep/roll your opponent. However an applied kimura probably should end the fight.

Wide variety

point the top of the head with his arm

dislocated shoulder, broken arm

- grab your belt or legs
- if it's possible try to keep your back on the ground