This music disc is the creepiest thing I have ever heard. This disc is the last thing this person did before dying. Don't know why notch would add this, except the reason of it freaking out people and giving them thoughts that we were not alone on the island. Last thing you here on the record is fire which leaves me to believe this is in the Nether. Does this freak you out?
Just go to creative mode and listen to it. Tell me what you think.