In 1965, the astronauts of Gemini 6 reported something they couldn't explain: Christmas music in the vacuum of space.
Right after they saw Santa Claus (a.k.a. the secret Gemini 7 spacecraft), they heard what sounded like "Jingle Bells" coming through their radio. It wasn't aliens—it was probably a prank by Wally Schirra, but for a moment, they were the first humans to experience a cosmic mixtape.