Some authorities believe it is just fluorescent gases rising out of swamps or old graveyards.
However, it is often seen in desert environments. This means that those who named it believed it to be part of an even larger power existing on this earth. I believe they are right in regarding it as a non-corporeal life form having elemental intelligence and willpower. Although it occasionally journeys about during the day, it tends to be shy, usually hiding behind rocks or within caves during the day, coming out at night. Like the legendary vampire, it often seeks out life forms, preferably humans, and tries to attach itself to them.