Spiciest cocktail in the world?

So this was supposed to be the spiciest cocktail in the world. Obviously I didn't try it as I was working and I think the less time I spend choking and crying while I'm working the better. They make it amongst other things at Zenna Bar in Soho, London. The piece of paper in the photo is a liability waiver that you have to sign before they'll let you drink the cocktail.