This is an animation of a phenomenon we all know: no matter how hard you try to shake it off, you can't get that song out of your head. Psychologists call this "earworm", referring to the songs that arrive without permission & leave when we tell them to.
The video above, called Jazz that nobody asked for, is created by a Danish design agency called Benny Box. The music that taunts the main character is "Quaker City Jazz" (1937) by Jan Savitt & His Top Hatters Orchestra.