Your son must be really really naughty if Krampus came down in front of you for him. Maybe get your son some therapy? And keeping a body in the attic could draw police from the smell. Most people would think you killed some freaky animal or demon so I wouldn't worry too much about removing it from your house but I would be worried about Santa or Krampus coming back to life. On American Dad both Krampus and Santa are eternal. You don't want Krampus gunning for you every Christmas like Santa does with the Smith's. You need to figure out and solution. Research Krampus and Christmas lore and find someone who deals in the paranormal and show them what you have in the attic.