Do you remember when people flipped out about secret messages encoded in backwards grooves on albums? Hell, do you even remember albums? It used to be easy to play a song backwards – just reverse the drive on your turntable and go. Artists have been hiding backwards messages for decades. Some claim it's accidental, but some are just too perfect to be a "mistake."

Here are some of the best, from scary Satanism to wacky jokes.

Slayer – Hell Awaits

Of course the masters of thrash metal would dabble with old-fashioned backmasking. On “Hell Awaits” off of the same-titled 1985 album, the first minute and change of the track features vocalist Tom Araya chanting “Join us” over and over again. Dude, I sent you guys my demo tape, I’m trying!