We had a "secret menu" item like that at the first place I worked at (which was rather CoD like)[1], and probably should have had a waiver. We called it "The Heartstopper", and it was made by placing a jug of iced espresso shots in that back part of the fridge where things iced over, and basically freeze-distilling it. It was coffee scumble, and would instantly make one seriously knurd. I made the mistake of giving one to one of the younger crowd because he had been pestering me long enough, culminating with "I'm Italian, I can handle it". He was maybe able to finish half of it, and that batch hadn't even properly matured yet.
Fast forward to three days later, when his gf informed me that he hadn't slept the entire time, and also encountered *other* problems of a more intimate nature due to vascular constriction.
[1] We had some rather odd employees, particularly at nights. Goth-ass me was somewhere in the middle when it came to normalcy, although I was one of the two odder-looking ones[2], if we're only going by appearance.
[2] One other dude on nights did look like a scary-ass skinhead with a 6" knife on his belt.[3] Of course, once you got past the snark, he was a total pussycat who didn't hate anyone.
[3] California may have pretty strict gun laws compared to most of the US, but open-carry of sheathed blades is perfectly legal here. And by blades, I don't just mean knives. Swords are acceptable as well and I have done it in the past, but the filth does seem a bit jumpier these days.