You could either make a copy of the Handbook for the Recently Deceased or buy one and dress up as any dead person.
Some Beetlejuice costume inspiration:
Beetlejuice! Beetlejuice! Beetlejuice!
BEETLEJUICE IS THE BEST!! ^^
I wonder if my lusty weakness for French men stems from my childhood love for Jacques in the Beetlejuice cartoon?
Beetlejuice Valentine by Satan’s Niece, 2016