Music on my Thunderbolt that doesn't exist?

[hindotmo]

I just downloaded all of my music onto my Thunderbolt, and when I go to look at all of the music, it displays it all just fine, artists, songs, everything. But, under artists, it displays one called "Unknown," and the song title doesn't appear, either. The song does play, but I don't want it on there, it's not one I actually put on there. When I plug the Thunderbolt back in, it shows me all of the songs that I downloaded, but not the unknown one. I'm not sure where to start with this.

Thanks!