This cache was placed for the Cacheoween 2015 event.
Trick or Treating is for children on Halloween in many countries. Kids will dress up in costumes and travel from house to house and ask for treats such as candy with the phrase "Trick or Treat!" The "trick" is a threat to perform mischief of the homeowners if they do not give out treats (the threat is usually idle). This has been a tradition in North Amercan since the late 1920's. Typically a home that would like to participate in handing out candy leaves a porch light on to show you welcome trick or treaters.
The tradition of going door to door collecting food already existed in Great Britian and Ireland, calling "souling", where childrend and the poor would sing and say prayers for the dead in return for cakes. Children disguised in costumes going from door to door for food and coins also predates trick or treating and is recorded in Scotland at Halloween in 1895. Masqueraders in disguise carrying lanterns made from scooped out turnips visited homes to be rewarded with cakes, fruit, and money.
In Mexico this practice is called calaverita ("little skull") and instead of trick or treat the children ask "me da mi calaverita?" which means "can you give me my little skull?" A calaverita is a small skull made from sugar or chocolate.
