Believers in backmasking think they can hear "Hail Satan" and other messages to Satan in a song by Aerosmith that was released as part of which album ?
Hail Satan:  Believers in backmasking think they can hear "Hail Satan" and other messages to Satan in some songs played in reverse, such as "Walk This Way" by Aerosmith. Walk This Way:  Written by Steven Tyler and Joe Perry, the song was originally released as the second single from the 1975 album "Toys in the Attic".
"Toys in the Attic"