Andy Baker, living a double life as the ghostly superhero Fury, buys a couple items from an old shop, unaware he let in a ghost or two into his life. Bit by bit, he loses himself in a growing Mastaar's lustful rhythm and starts undergoing quite the few changes of tune... (my first smut story, apologies if it's underwhelming. Fandom is "Ghostforce" by Zagtoon).