• Black cats are bad luck: The devil turning himself into a cat to talk to witches/witches having black cat familiars, demonic animals from the devil.
• Jack-o-lanterns guide lost souls: A man named Jack tricked the devil, causing him to not be let into heaven or hell. He wanders purgatory with a lantern he carved out of a turnip with a piece of coal from the devil to light it.
• Bats are ominous: If a bat flies around a house three times, someone in the house will die.
• Spiders If a spider falls into a candle lit lamp and dies in the fire, witches are nearby. If you see one on halloween it means the spirit of a dead loved one is watching over you.
• Wearing costumes trick ghouls: Ghosts and ghouls will think you are one of them if you dress up like them and then your soul won’t be stolen.
• Bobbing for apples tells your fortune: If you are the first to get an apple without your hands you will be the first to marry. Getting an apple on the first try will find true love and after many tries would be fickle in their love life. If a girl put her bobbed apple under her pillow, she would dream of her future husband.

Source: https://www.livescience.com/16677-halloween-superstitions-traditions.html