'King of Rock' by Run-D.M.C.
Run-D.M.C.'s bizarre error in "King of Rock" always seemed borderline to me. Could it really be a mistake? They're talking about the most popular group in the history of music, for one, and making an arithmetic error that a toddler could correct. The lyric in question comes near the end of the song, in which the lyrics read, "Every jam we play, we break two needles/There's three of us, but we're not the Beatles."
So not to be overly hairsplitting, but there were four principal Beatles. Which you know. And I know. And Run-D.M.C. surely knows. The most grating part of this lyrical mistake is that they could've easily said, "There's three of us SO we're not the Beatles" or "AND we're not the Beatles." And now I go, to spend all night daydreaming about traveling back through time to convince Run to change that lyric.