I'm Only Sleeping has the backwards guitar solo.

Yep. The song is “I’m Only Sleeping” from Revolver. George Harrison recorded a guitar solo normally, the tape was flipped, and that dreamy, psychedelic backwards sound is what came out.

It wasn’t a gimmick — they were experimenting with tape manipulation, and it just worked for the drowsy mood of the song. (Also fun: Paul McCartney has a backwards bass part on “Rain,” but no backwards guitar solo.)

So if you were thinking of the backwards guitar moment that sounds like it’s melting into a pillow, that’s Harrison on “I’m Only Sleeping.”