If you’ve seen the ‘Secret Sister’ gift exchange floating around Facebook, don’t bite — according to the Better Business Bureau (BBB), it’s actually an illegal pyramid scheme.

The scoop on ‘Secret Sister’

The Secret Sister scam originated in late 2015 and has been circulating since. The Facebook post asks users to send one gift valued at $10 or more to their “Secret Sister,” (aka a stranger on the internet) with the promise of receiving up to 36 presents in return.

“Anyone want to join in on this fun?” one version of the post, obtained by CBS News, reads. “You have to buy one gift valued of at least $10 and send it to your secret sis. (Hello, Amazon!) you will then receive 6-36 gifts in return.”

Though it may sound alluring to be on the receiving end of all of those gifts, it’s actually mathematically impossible, according to the U.S. Postal Inspection Service’s statement on chain letters.

You will most likely not receive any gifts in return. Rather, you’ll be putting personal information — like your home address — at risk, along with breaking the U.S. Postal Inspection Service’s gambling and pyramid scheme laws.

What you can do to avoid the scam

According to the BBB, you should never give strangers your personal information, as there’s always a chance this will open you up to cybersecurity breeches.

So, if you see a version of ‘Secret Sister’ in your News Feed, don’t fall for it. To help others avoid the scam, you can report the post to Facebook by clicking the three dots in the top-right corner of the post.

Stick to traditional gift exchanges this holiday season to stay connected with friends and loved ones, while effectively avoiding scam-related disappointment.