The setup probably isn't how you'd expect. These might seem random, but you need them all to make your poor NPC's cranium combust. Spawn in the following:

• A human
  
• An industrial generator
  
• A jukebox

Set the human about what would be 3 meters (9 feet for americans) away from the jukebox, and freeze the jukebox. Place the generator next to the jukebox, opposite side from the human. Freeze this as well. Optionally, you can go into the right click menu to make sure both are set to indestructible. Connect the jukebox and generator with an electrical wire.

Time to end / intensify that helpless pixel guy's suffering! Use the context menu to choose a track you can vibe to, turn on the generator (wait until it's fully charged), and turn your volume down. Like way down. Once you have this done, turn on the jukebox, and hear you song blast in its full eardrum-destroying glory. Not long after you turn it on, the humans head should pop and become a fine red mist. Congrats, you're a frickin' psychopath!