Please don't show this to any black metal bands. They've killed tremolo picking already.
This Indonesian dentist is well aware of the fact that dental drills can be a little bit... err... intimidating. So, he created a drill that, instead of making the typical whirring and buzzing noises a drill makes, plays audio of the patient's favorite songs from an MP3 player. Nothing like a little Gangnam Style to ease the nervousness of having a whizzing metal object shoved into your mouth (no, don't even go there...).