Did you mean Walpurgisnacht?
Walpurgisnacht
noun
°Walpurgis night, a feast of witchcraft in German folklore; any orgiastic or bacchanalian party.
"1942: The proper sequel to the Walpurgisnacht obsequies of Franz Ferdinand would have been the dismissal of Prince Montenuovo — Rebecca West, Black Lamb and Grey Falcon (Canongate 2006, p. 365)"