It was used on me last night, in some pvp in the wardens. It turned my screen black, which I assume is it's intended effect. No chat windows, no control, just black..which makes sense. It then crashed me to desktop. Which is the bugy part. Had to reboot the game, and when I did, I was just subdued, no longer blacked out. This happened last night around 9pm PST, in PVP with Charlotee, Jack, myself initially.
Actually, if you press M, you'll find it puts you in a pitch-black 2x2 room with no other UI elements.
It crashed me to desktop..not sure M would of helped
Could it have been when the whole server crashed therefore not a bug?
To my knowledge, it was only me, that was an ongoing fight, and I was the only one to crash at that time.