This was inspired by a picture by  lorule
http://www.furaffinity.net/view/18168618/
The design of this Monster Kid is also entirely Lorule's responsability. I did ask for permission to post this. You can even check the comment of the picture linked above.

The idea is, after ALMOST beating a Genocide run, you are about to answer the final question, and then, in comes Monster Kid. Then he becomes the real last boss.

This all of course is not canon, and is NOT a spoiler. This was just someone wanting to draw Monster Kid in an amazing way, and me wanting to make a sprite of it.

The HUD was not made by me, but everything else was.