Don't blink. Blink and you're dead. Don't turn your back. Don't look away. And don't blink. Good Luck. The Lonely Assassins, that's what they used to be called. No one quite knows where they came from, but they're as old as the Universe, or very nearly. And they have survived this long because they have the most perfect defence system ever evolved. They are Quantum Locked. They don't exist when they are being observed. The moment they are seen by any other living creature they freeze into rock. No choice, it's a fact of their biology. In the sight of any living thing, they literally turn into stone. And you can't kill a stone. Of course, a stone can't kill you either, but then you turn your head away. Then you blink. Then, oh yes, it can. Don't blink. Don't even blink. Blink and you're dead. They are fast. Faster than you can believe. Don't turn your back, don't look away, and DON'T blink.