The Boo Radar is a device made by Professor E. Gadd in Luigi's Mansion. The Boo Radar is a device that tells you if a Boo is somewhere that is hiding the area your in. The radar might detect a Boo but it will either be a bomb or a ball resembling a Boo. It makes different colors to show if a Boo is nearby; blue means there are no Boos near you, yellow means there is a Boo somewhere. and red means you are right next to a Boo.