I went with a classic, vintage, psychedelic San Francisco vibe for the art. 15x22 on French Oatmeal paper. Mule's legendary Halloween shows involve covering a certain band throughout the sets. This year's theme was The Who.
The poster art played off The Who's lyrics that I think applies perfect to the misunderstood monster from Frankenstein :
No one knows what it's like
To be the bad man
To be the sad man
Behind blue eyes
--From Behind Blue Eyes
and the line
"Don't Cry" hidden in the top
--From Baba O'Riley
There is also a Who icon as the Third eye on the monster.
Available at the Oakland show and upcoming on the Drowning Creek Web Store.