Destin from the SmarterEveryDay YouTube channel shows off the fascinating properties of what's called a "Prince Rupert's Drop". Essentially formed by rapidly cooling a drop of molten glass, it exhibits rather peculiar behavior when you try to break it. Take a hammer to the bulbous end, for instance, and the glass won't even flinch. Make the smallest nick to the tail, however, and the entire structure not only shatters, but completely explodes in a wave originating from the point of fracture.
This all happens too quickly for the human eye to see, but thankfully Destin is armed with a camera able to capture the phenomenon at 130,000 frames per second. The effect is quite beautiful, and the mechanics behind are intriguing. But don't just take my word for it, check it out yourself!