Just over an hour ago, at just before midnight, I was filming myself shining a laser pen around the living room and having fun watching my cat trying to catch it. This video is 2 minutes and 27 seconds long. While filming it I noticed nothing out of the ordinary. But when I watched it back, about 1 minute and 36 seconds into the video, as I was panning to the left and the settee came into view (with a little blanket on it for the cat), I noticed a growl. It's quite clear and it doesn't sound human. I've listened to it several times and I can't find a logical explanation. It is quite clearly a creepy, malevolent, demonic growl.
I am well creeped out now. It's 1:15am.
Here's a picture of the living roon which I've just taken.