Rock musician who has visions of Elvis and becomes a supervillain, and who also triggers a generation gap debate between Batman and Robin about the evils of rock music. Robin's thesis: rock music is OK. Batman's counter: rock music is eeeeeeeevil! Amazingly, the comic book Batman: Fortunate Son is not from the '60s or even '50s; it came out in August 1999! Though, unlike other "rock music is the devil" narratives, Batman's objections were not due to religion, but to the fact that a) he listened to rock right before his folks got murdered; b) Arkham Asylum has a whole ward for Elvis impersonators; and c) he had some kind of relationship with a thinly veiled Sid Vicious right before Sid met Nancy.
Yeah. Item c) happened.