Google make some logos. Six logos to celebrate what they called Halloween. Scary pumpkin, monsters, witch, goblin to describe Halloween message.
You can scroll the history how the Halloween started on the past in Wikipedia. Why must October 31th? What did they do at that time?
Halloween become popular in the day. Many movie with this theme have been made. Many events, parties held to celebrate. Many costumes create very serious and special to be as bad as evil.
For me. I do not like Halloween any way. Huge of money spend for nothing every year, just for to be like evil. Better give the money for social activities purpose. Helps other for better life, health, education, etc.
You can check other logos prepare randomly. When you refresh the browser page, you can see different logo.