Run! It's Queen Boo!
Queen Boo is a boo that rules over other boos. She rules them because she is married to King Boo, who is the leader of the boos. Queen Boo is actually uglier then King Boo, which we didn't know was possible (except (here), and Queen Boo is weird too. She thinks Bombs are explosive! Crazy, huh?
Queen Boo became a boo when she tried to rob a bank, but forgot to bring a weapon. So, she made a Shotgun appear out of midair, and started shooting everything in sight. Bowser, who was disguised as a police officer, shot her, turning her into a boo. Now, Queen Boo is one of the most powerful boos ever, but she still has no power.
Queen Boo once ate the Easter Bunny, but the Easter Bunny stabbed her with its Sword of Epic, and Queen Boo's guts exploded. (Don't you hate it when that happens?)