A Chemical Reaction That Will Give You Nightmares

Chemical reactions can do all sorts of things. They can blow up, change color, make nasty smells, and give off gasses that will make your eyes tear like someone (OK, women, really) who just saw "Beaches."

Chemistry — love it or hate it — has one thing going for it: It's never icky. Scientists who like to handle icky things become biologists. There you get to play with chicken heads or things with guts. Icky.

Or, so I thought, until I made the mistake of watching a video that was going around the chemistry world several years ago. For reasons that no one I know can explain, this one goes far beyond icky. More like, vile and disgusting. Never saw anything like it.

There is a chemical called mercury isothiocyanate. It is an obscure substance (I don't know anyone who has ever used it), and looks like nothing special — a white powder.

But, if you light it on fire, it does not blow up; it turns into something from a bad nightmare. If you have to turn your head away from the screen while watching "Alien," you might want to skip this.

Can anyone explain what the hell is going on here?

Sweet dreams.