Yes, you have heard it. You've cringed at it. You know you have. That screech -- that most dreadful and painful screech -- before which all men and women, young and old, flee.

See, there are a few things in this universe which, each day, we must all do our best to avoid. One is getting kicked in the groin. Another, and the most relevant to this entry, is the unholy sound of fingernails on a chalkboard. It is a sound that tries men's souls.

Heck, even Aristotle, the great fourth century philosopher, noted the "aversive" qualities of the scraping sound. And researchers from Northwestern University have also studied the matter, which they have dubbed impressively the "psychoacoustics of a chilling sound."

Now, fingernails on a chalkboard is bad. According to the Northwestern University scientists' research, the rubbing of two pieces of styrofoam together is bad too. But equally pervasive is a certain scene in Episode III -- the one where we learn the true power of Yoda's claws.

When Yoda, tired and defeated, falls from the Chancellor's podium, he finds it necessary to scrape his long, sharp claws against the thing. These mere five or six seconds of viewer pain form what I am now going to boldly call the worst moment in the saga.

If there is any good in this world, Lucas will one day go back and make a "special edition" version of the prequel trilogy, presumably for release in a special box set of futuristic "LK3P" discs or something, and he'll remove the scraping scene.

A man can hope, anyway.