Rock Pig
I was given the fridge magnet pictured on this page by a very good friend a few years ago, and was slightly surprised, and underwhelmed at the time, as I am sure my face gave away...
But now I am putting out pig-related geocaches, it has been a great source of inspiration.
The second track off 'The Downward Spiral'. I loved this album when it came out, and saw Nine Inch Nails live in the Barrowlands when they toured to support it. Trent Reznor loves his pig imagery. So much so that the support band that night was called PIG (Though in double-checking this I learnt that Type O Negative supported on some dates of the tour, which would have been so great. Not that they have any pig-related songs...).
Although I love these songs, I am over 18, and rock isn't always for children, so if you seek out this music (which I heartily recommend you do), here is my parental advisory sticker:
This is the most difficult cache on the music section of the trail terrain-wise. Please be very careful, especially if it is wet.