I don't know if this counts but don't read any further if you don't want to permanently ruin a beautiful song...
Utada - Final Distance
Misheard: "We are the molemen"
Real: woah woah woah
Don't ask me how, but her singing in that one part makes it sound like she's saying "we are the molemen.
You can hear it at around the 2:42 mark, nothing special but still, it kinda killed the song for me.