"Ignis Fatuus," also known as "will-o'-the-wisp," refers to a phenomenon where phosphorescent light appears at night, often in marshy areas. This eerie glow is caused by the combustion of gases emitted from decaying organic matter, primarily methane. Historically, it has been associated with folklore and myths, often leading travelers astray. The term "Ignis Fatuus" is derived from Latin, meaning "foolish fire." People have reported seeing these lights flickering and moving, which can create an illusion of a distant flame. While intriguing, these lights can be misleading, causing individuals to wander into dangerous terrains like swamps or bogs.