The only really good song I can think of that people actually sung at halloween is...well quebeqois so it's in french, but:
C'est L'Halloween
Wish there were more songs like this. Christmas kind of has a monopoly on being the holiday that make people people break out into song...which is lame.
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Cats land on their feet. Toast lands peanut butter side down. A cat with toast strapped to its back will hover above the ground in a state of quantum indecision