Me as Miss Argentina, the receptionist from Beetlejuice.

Thomas Edison

Here's an idea:  Thomas Edison with an electrocuted sheep.  You could carry a stuffed animal or it could be a couples costume.  One person is T.E. and the other is a sheep.

Poe Ideas

Sudden idea.  Costumes inspired by Edgar Allan Poe poems and short stories.  Simple would be to dress as Poe himself or a raven.  A couples idea would be Poe and Lenore.  I picture a Victorian lady with a rotten torn dress.  Obviously they have both returned from the grave.  Dress as "tintinnabulation" by covering yourself in bells.  I'm still trying to picture a tell tale heart.  Dress as the Pit and the Pendulum by creating a blade (cardboard and silver spray paint)  that looks like it is imbedded in your torso.

For more stories look here:
Edgar Allan Poe poems and stories