Who knew that throwing small rocks at a massive internally burning rock could cause some of its melted rocks to start flaming again? Well these people quickly found that out, after tossing a rock down into a sleeping volcano. A short and satisfying flight and impact are followed by a small circle of exposed molten lava quickly expanding into flames, churning the surrounding magma until there is a very active and somewhat sizable patch of bubbling melted rock in the middle of the lava lake.

While it is unlikely the actions of these people could cause any damage the volcano wouldn't soon naturally do on its own, the expression 'let a sleeping dog lie' comes to mind. Or in this case, you know, a huge volcano! Perhaps there are things we as humans really shouldn't be messing around with for our own amusement, and I'm willing to throw volcanos onto that list.