It’s a submitted video from a Gmail account. There have been rumours that there’s a root kit in the video. I don’t know if this is true or not, and I’m looking around for more information. I’ll update as I find things.
From what I’ve gathered, it could be one of several things:
1) The video contains a virus or some sort of malware.
2) The video itself is just spam, but clicking on the sender will give you some sort of virus or malware. (Personally, I think it’s this. This post states that it’s an embedded video from youtube, so it’d probably be difficult to sneak a virus in there.)
Or 3) The whole thing is just spam.
Either way, if you’re ever worried that something is a virus or if you’re suspicious or something sent to you, just delete it. Chances are it’s not worth the risk.
For things like this in the future, there have been different posts that have said that Kepersky’s TDSSKiller works well for things like this. It’s specifically built to find root kits, so I’d say get it if you’re worried.