Ok I did this one year when I ran a bar.
Shaved my head and put black make up around my eyes.
Wore a black t-shirt and a long (mid thigh at least) coat.
Go as Uncle Fester from the Addams Family.
Works great if you can find novelity light bulb that has a small battery inside and lights up w/ a small piece of foil.
I kept the foil in my mouth, when I put the bulb in I'd use my tongue to complete the circit.
P.S. No Frankenfurter was the freak!