Here's a special Halloween treat! Pretty Dirty Secrets, the smartly named web series attached to ABC Family's addictive teen mystery drama Pretty Little Liars, is loaded with special clues about the series. Before the last of eight webisodes premieres on Oct. 16, we scoured all under-the-radar hints about the series' upcoming Oct. 23 Halloween episode (guest-starring Adam Lambert), as well as its new season, which launches in January.

Without further ado, here are the 11 photo clues any good Pretty Little Liar should notice:

1. QUEEN OF HEARTS
Did you notice the creepy gal hanging out in the web series? We've seen the Queen of Hearts in the past with ''A'' culprit Mona. Just know this: She's important to what lies ahead.