1. The Halloween is on 31st October.2. They meen that the kids go and knock others door, and say ''trick or treat''. and if the person answer ''trick'' it means that the kids can make a trick if they want to. And if the person says ''treat'', the kids will get candy or something else like fruit, money.3. Because they wanted to look scary, and they wanted candy so they dressed up.4. Black cats.5. Some people say he did this to try to stop people celebrating Samhain!