New feature?

Is this a new feature? William got the same thing, see here

If you go to the main page, chobots.com, not chobots.com/play, and click play now you can see it. It is there for .5 seconds or until you move your mouse. What is it?

Here is a video that i recorded and used to prove that it is not an edit.

PS: It's at the very end.