Make red headed step child boo. When you summon that boo, the others run away. Or welfare boo. When you summon welfare boo, the male boos run away and the baby boos multiply, making welfare boo grow in strength.
I dont know why they gave us baby boo when we already had a boo junior they should have went with a boo pet or grandpa boo or something
Boo Senior and Misses Boo haven't been done yet (some people confuse Miss with Misses. We have Miss Boo and need a Misses boo.) Also, Doctor Boo with a sonic screwdriver or a scarf could be cool. Maybe Sir Boo wearing an open plate mail helmet, or Boo Esquire. A rockabilly/country music Boo named Boo III (a spoof of Hank III).