King Boo loves to scare and toy with his opponents, rather than defeating them quickly. In Luigi's Mansion, he chooses to use his powers to blow Luigi back to the foyer instead of trying to finish him off while at maximum power, and enjoys watching Mario struggle from within the painting he was trapped in, stating Mario's desperate attempts to break free were "satisfying." Despite his huge size and immense power, he still covers his face in fear when looked at, much like a normal Boo, showing that he still has a shy nature like his minions; however, also like a normal Boo, he attacks when his foe's back is turned. King Boo has a distinct cackle, which is significantly lower in pitch than other Boos. He also has an echo in his roar.
Speaks in airy, playful boasts, then lands suddenly on sharp specifics; heavy use of pauses.
