King Bob-omb is the the very first boss you face off against in Mario 64, making him a rather special character for many Mario 64 veterans. Not only is he your first boss, but also typically give you your first star. He is sitting on top of the tall mountain in Bob-omb Battlefield. The player must traverse many obstacle’s climbing all the way to the top to face off against him.
One of those obstacles involves two rolling balls that look suspiciously a lot like Kin Bob-omb himself, minus the facial features. Here’s an image breakdown of what this theory entails:
The idea here is that after you defeated him, he became a full “dud” and became the third ball. A rather deep, yet simply sad story to endure. Of course, it’s just a theory, but one that does make a lot of sense.