Also known as the Common Piddock, Pholas dactylus is a clam species whose natural instinct is to give off its own light where none other is present. A mollusk that lives in dark waters, the clam emanates a soft glow to light up its surroundings.
But this gift is not just reserved for the water. Fishermen have written about the luminescent clams for several thousand years, and modern people continue to be astonished by the blue hue that flows forth from the creature. The glow is strong enough to light up a glass cup and its immediate surroundings.
It was only natural that humans would take this ability and come up with a way to amuse themselves with it. Since ancient times, people have been stuffing the clams in their mouth to make their breath glow. Some describe the experience by saying it looks as though one is literally breathing fire, as blue light pours out of the mouth in an impressive flame.