This is supposed to be a filk for Terry Pratchett's Discworld. The words don't begin until a minute into the music. But it is catchy. A Wizard's Staff Has a Knob on the End starts off sounding like early Final Fantasy music, and when the words begin, it picks up a sort of Clancy Brothers feel. One of the top comments is, "Seen on a chalkboard in Hogwarts: "I will not teach first-years to sing 'A Wizard's Staff Has a Knob on the End'."
And as a bonus: here is Death's Job Interview from a production of Terry Pratchett's "Mort."