Boo Boo is the pet robot dog of Margaret and a lethal weapon that can be found at the dog park in Little Tokyo. Once the Player obtain's Boo Boo's favorite cat toy, they will come up with the idea to combine the TNT Teddy with the toy to make the Kitty Launcher. When fired near a group of enemies (regardless of whether they are OverCharge Drinkers or Scabs), they will be killed instantly upon Boo Boo's arrival followed by a blue mushroom cloud.
Boo Boo makes another appearance in Dawn Of The Rise Of The Fallen Machines. Lou and Fiona give him to the Player to use to take down the forcefield protecting the final set of Kill Codes needed to shut down Fizzco Robotics. Boo Boo can also be employed using the Come, Boo Boo Weapon Amp, available in the same DLC.
Boo Boo is also a possible effect when activating a Pandora's Box trap.