Google knows pretty much everything about you, so it makes a lot of sense that "what you're wearing for Halloween" is part of that.
Google analyzed searches for Halloween costumes and found the top 500 things that people are planning to dress up as this year.
Here's the top 10 . . .
6. Harley Quinn (The character from "Suicide Squad" and "Batman".)
(You can also see the top costumes in your area by going to the site and hitting the little toggle switch in the top left over to "locally.")