Security Cam Footage of Strange Mist Over House

What is This Strange Mist?

YouTube user yfall2010 posted this video on May 17th, 2013 of a strange mist he filmed with his security camera, hovering over his house.  For all intents and purposes, it doesn’t look like any normal vapor cloud, which begs the question of what then is it?

In the comments for the video he writes:

This was taken from my security camera. It looks like a demon and then a ufo flies into it. At the 3:30 mark that’s when it gets interesting but you should watch the whole video to see what it does from start to finish This is mind boggling. If I could do CGI then my videos would really be kick ass. I just need to know what the hell happened because this shit was over my house and too many strange things have been occurring in my area.

I admit that this video has me stumped.  My instinct says that there is a rational explanation, but aside from saying that it is a funk mist and leaving it at that, I would just be guessing.

One punt would be that it is an effect generated by the night vision in the camera as it catches a patch of mist moving over the house.  It may be possible that the low light features of the camera are interacting with lights playing on the mist to give the impression that it is moving and fading in and out.  Again, I will freely admit that this is a complete punt.

Have a better explanation for this strange mist?

I know I am leaving this one wide open, so post your comments and let me know what you think we might be seeing in this video!  Is it simple mist, a ghost, a UFO, Bigfoot using stealth mode?  Post your best guess below in the comment box.