Moviefone reports that Shadix died after a bad fall in his own home in Alabama. His sister, Susan Gagne admitted that he had mobility issues and had likley fallen out of his wheelchair and "hit his head in the kitchen."
In addition to Beetlejuice, Shadix collaberated with Tim Burton on Nightmare Before Christmas (as the Mayor) as well as Planet of the Apes (as Senator Nado). Before he retired from Hollywood around five years ago, he was famous for voicework as well.