YouTube video playing in background from Spotlight search

Maybe I'm having a complete brain f-a-r-t here but I can't figure out what's going on at all. I did a Spotlight search and in the results a YouTube video from my browser history appeared. I accidentally clicked or hovered over it before clicking the correct result I wanted but suddenly in the background the video was playing. Or at least the audio continued playing.

No window in any open application was running it. I quit my browsers and iTunes, I relaunched the Finder, and I removed the search terms from Spotlight. Continued to hear the audio, couldn't find the video or loaded YouTube page on any of my Desktops or backgrounds. Launched Dashboard to see if it was running in a Widget but no luck there either. When it ended I tried to reproduce the problem:

1. Clicking the Spotlight result for the video opened it in my browser, closed it no problem.
2. Tried hovering over it, the menu fly-out loaded a preview of the YouTube page/video which played but then stopped after moving my mouse away.
3. I hovered over the result again but this time clicked and dragged a tiny bit, a faint Safari icon appearing as I did. This duplicated the result and the mystery audio continued playing after I let go of the icon. I didn't drag and drop the icon anywhere, it just moved back into the results list. I essentially reproduced a clumsy, accidental move made with my drawing stylus.

Any ideas on what the hidden background audio (and possibly video) is playing in? How can it be stopped (other than restarting)? Thanks.

Message was edited by: dugost Can't believe f-a-r-t gets censored. Forums set to 'Victorian' mode, Apple? ;)