I've just discovered your wonderful site and wonder if you could help me with a kindertrauma my mum experienced as a kid.
It was a fairly old film, set in some kind of circus or carnival. There is a little girl who is always skipping around singing a song – it might be "Bye Baby Bunting" — and annoying everyone.
In the scene my mum remembers, a scary man (possibly a clown) snaps and starts jumping heavily on this kid, singing her annoying song in a kind of staccato as he stomps on her, finally realising she is dead. I think this happens behind a parked car.
My mum was going crazy trying to remember the name of this film.