10 Best Super Mario Fan Theories That Explain Everything

Boo is a ghostly enemy in the Mario franchise that chases the player but stops dead (pun intended) if anyone makes eye-contact with him.

Now, Boo isn't a ghost in the traditional sense. He is more like a will o' the wisp; a spirit who never lived as a mortal. But real ghosts do exist in the Mario franchise, especially in the Luigi Mansion spin-off.

In these games, Luigi must battle his nemesis, the ruler of the Paranormal Dimension, King Boo. Because this self-crowned phantom is one of the most powerful entities in the world, it's clear he is not a random will o' the wisp, suggesting he was once alive.

It's assumed he is called King Boo because he is the leader of all supernatural forces. But what if he is called King Boo because he was a royal figure in his past life? Because he often allies with Bowser (who is a king), some people believe he could be his father's ghost.

Another idea is that he is Princess Peach's dad. After all, if Peach is a princess, her father must be a king. So how come we've never seen him?