King Boo

King Boo is a recurring antagonist in Not So EPF.

(Not So) Elite Penguin Force
King Boo appears in (Not So) Elite Penguin Force completely by accident. The Test Bots attack The Party on Rockhopper Island, but they just happen to get Tubba Blubba's battle music, and Mario says it would fit a spooky battle better, so they disappear and get replaced by King Boo. He turns everyone into a Boo, but gets eaten by LMGT. He returns to stop the Fourth Wall.

King Boo is the only megaboss who is not affiliated with Herbert in any way.