Sulfur burns with a nearly invisible blue flame

Igniting solid sulfur yields a creepy, ghostly blue fire that is notoriously difficult to see in daylight. Worse, as it burns, it melts into a blood-red liquid while spewing suffocating, highly toxic sulfur dioxide gas. It is exactly the kind of unholy chemistry that explains why ancient civilizations were absolutely terrified of brimstone, assuming it was a direct export from the underworld.