Halloween costumes are derived from the idea of the Celtic Druids who claim that participants were required to wear ceremonial animal heads and skins, to acquire the power of the beast they represented.
"Trick or treat" is derived from the Irish tradition, a man that led a procession to collect contributions from farmers, for fear that their crops are damaged by demons.
"Dunking for apples" was an ancient practice to know the future, due to Pomona, a nymph of fruits and flowers. The participant, who managed to catch an apple between his teeth found in a barrel full of water, could expect a romance, successful, with the beloved of his choice.
Cats represented human incarnated evil spirits or "close friends" witches.
Hazelnuts were used in divination fiction. Part of what you eat during Halloween, contained objects placed inside food as a means of telling fortunes.
Masks have traditionally been animists means to protect themselves from evil spirits as superstitious or that the wearer can change personality, to communicate with the spirit world.
It would also add to this list the opportunity to live within a wild night (called "Prom Night and pleasure"), all perversions and defy all taboos.
