I'm listening to...

I just got my new headphones for my ipod. I tested them and all of a sudden my son André (7 years) approched me and wanted to listen. OK I said but it's heavy music. He put the headphones on and all of a sudden I see a big grin on his face-
"dad, can you add this to my MP3-player?" he asked. Dad nods and say. YEEEEESSSS! I'm a proud father.. What he listened to??? OPETH - Ghost of perdition