What is the most ridiculous case of where someone you know has thought a song was by the wrong artist?
I remember when I played "Do What U Want" for a friend when it first came out and asked him to guess the artists, his first guess for the female part was Carly Rae Jepsen.

Then he guessed Christina Aguilera, Britney Spears, and (after I told him it was by a "very, very famous female artist") Madonna before I had to tell him it was Gaga.