Obnoxiousness By Osmosis?

At lunch today, Cash launched in to the "Batman Smells" version of Jingle Bells. How does a four-year old know this version of the song? Travis and I certainly don't sing this version. I asked him who taught him this song and he said, "I got it at the Jingle Bell store where they have all kinds of Jingle Bell songs. This is the party Jingle Bell song."