Google has made modifications to the way search results look when you query for music videos. If you search for music, it will show you a card similar to the ones seen on Google Now.
The Google Now-style card with large YouTube thumbnail will be displayed as the first result and gives you an illusion that the YouTube player is embedded in the search results. You cannot play by clicking the play button shown on the large YouTube thumbnail but you will be redirected to YouTube page instead upon clicking.
The videos which are official, like those from VEVO, are supposed to get these type of cards. But it appears that some videos from other uploaders are also receiving this special treatment.
A Google spokesperson said:
This was already available in September 2013 when you searched for an artist and then clicked on a song – you’d see a preview of the music video if it was available to display. Yesterday we made it easier to get to – you can now just search for a song directly and see the video screenshot right away.