There's a tv commercial with people muddling the words to "Rocket Man". That's not been an indecipherable lyric to me but there have been many others, and I'm not alone.
Throughout my life much of what Mick Jagger has meowed out has evaded me. And I can't even be bothered deciphering what Mariah Carey yodels. I have bastardized many Dylan/Stones/Aerosmith/anyone who sings rock that way's lyrics. And for years I thought it was just me. Then one evening someone brought up wrong lyrics and everyone chimed in with what they've been mishearing all these years. There are whole websites devoted to this:
And notes on commonly mistaken lines:
But my personal favorite was from a guy who said he'd always thought the words were, "The girl with colitis goes by", in "Lucy in the Sky with Diamonds".