HTC Tilt 8925 / TyTN II

I added a 2 gig storage card to my tilt and added a bunch of music to it. Using the HTC home screen I'm playing the songs and then out of nowhere strange music starts to play - songs I've never heard of before and most definitely would not have included on my storage card. I've looked all over the phone and can't find the various songs that pop up.. What gives? Is WMP downloading music out of the blue and playing it? Has anyone else seen this or am I hallucinating? :-)