Excerpt Knock, Knock Syfy Insider Exclusive Create a free profile to get unlimited access to exclusive videos, sweepstakes, and more! Sign Up For Free to View Knock, Knock When Matt finally tried to find out what was behind the padlocked door, he found more than he bargained for. Watch the Full Episode
0:35 Astrid & Lilly Save the World Astrid & Lilly Save the World Teaser: The Heroes You Didn't Know You Needed
