A Muse is a character who inspires others, normally seen as positive a Muse can easily become negative if twisted in a similar manner to an Evil Genie - often appearing to an individual or group a Muse inspires them, often via horrific events of circumstances.

A good example of a villainous Muse is someone who performs grisly misdeeds, which another characters take as inspiration in their work - whether they become a "copycat" or something else entirely (such as horror writers gaining inspiration from demons who show them grotesque or frightening imagery - which they use in their work).

Often a villainous Muse will see their misdeeds as a type of art and share their "gifts" with those unfortunate enough to be around them, usually a villainous Muse is feared by all around them due to them idolizing things traditionally seen as taboo in society - though some exceptionally twisted or desperate individuals may willingly call upon such a Muse when in need of inspiration (as seen above).