Frau Holda; others, like the Welsh Pwck, the Lancashire boggarts or the more widely found Jack-o'-Lantern (Will o' the Wisp), are sprites who do no jmore harm than leading the wanderer astray.
String some lights, add candles and a jack o'lantern to finish it off.
A jack-o-lantern lit from within using real or LED votives makes a great starting point, and can be combined with other elements such as small candles or miniature pumpkins.
Consider hollowing out a pumpkin, much like you would do for a jack-o-lantern, but carve hearts instead of a face.
Choose a long-sleeved black T-shirt with a bright orange jack-o'-lantern on the front and pair it with a pair of jeans for a little boy.