Audio jokes don't work in a silent medium. You'd quicker think he has a speech impediment before you'd think he was quoting a song lyric.

This also stands for any time a character hums, like so:

"Dun dun dun dundeedun dundee dun."

If you get that, congrats. If not, stop doing this in comics.

The real joke in this comic is that Batman thinks Vitamin C fights cancer. That, or Kris Straub is an alternative medicine kook.

For the record, it doesn't.