If you're rolling by Facebook's headquarters in Menlo Park and see a big thumbs up sign - dripping with some fake blood and a bone sticking out of the wrist - then you'll know the social networking giant is wishing you a Happy Halloween.
MORE: Bay Area Halloween Events Guide
Just as Google likes to mark holidays by changing the Doodle to refect the day or anniversary or mood of the country, Facebook is now jumping in to "like" the national day of trick-or-treating coming up on Thursday, too.
Facebook headquarters is on 1 Hacker Way off state Route 84.
