Prince Rupert's Drop

Have any of you ever heard of this? (Samuel, you seem the most likely.)

A Prince Rupert's Drop is what occurs when you drop molton glass into water. A long, teardrop/tadpole shaped piece of glass will be formed. The bulb end is strong enough to withstand a strike from a hammer without breaking. But if you so much as scratch the tail end, the entire thing will shatter into powder-sized pieces. Isn't that cool? A video of it can be found here. And an explanation can be found here.

I have no idea why this is so cool. It just is. I would love to actually watch a glassmaker someday. It is extremely fascinating to me.