Pop Goes the Weasel by Kevin MacLeod
Heavy bass drums and an string bass set the tone for this dark and menacing tone. The familiar refrain then plays, but is made expressive and almost violent as it is played on several string basses and cellos. The pace is rather quick and forceful, and after the quick ending, a jack-in-the-box plays, normally child-like, but made creepy because of the sinister music that came before.
Best song ever!!!