Twitter tweeted out a message today about a special Halloween feature if you Tweet “#trick” or “#treat.” It was difficult to figure out at first, but if you tweet either from your Twitter home page (this is key, you can’t enable the feature when you are on a client), your home page background will go “ghoulish” and the avatars on the Tweets on your page will turn into zombies and ghouls.

The way to trigger it is by tweeting ONLY “#trick” OR “#treat” with nothing else. #Treat is the top trending topic on Twitter so it looks like the masses haven’t figured it out. If you only post #trick or #treat, it doesn’t actually Tweet it out (if you post from Twitter’s site). Happy Halloween!

There are a few variations of backgrounds that Twitter is featuring in the trick. Here are the ones we found.

Thanks @orli!