Blue Wisp

A floating monster that emits a constant, eerie light. In more superstitious times, these wisps were thought to be souls of the dead, unable to move on from our plane, and were greatly feared. But we now know they are a subset of elementals. They do not require sustenance in the traditional sense but appear to absorb magic from the atmosphere to convert into energy. Wisps are very sensitive to magical vibrations and often swarm around powerful magic-users. Luckily it is quite easy to see them coming, given their radiant appearance.