The Gaddlight is a small flashlight that is green in color with an image of a Boo crossed out on it. If someone uses a Boo on a Boo's Crystal Ball or summons Boo from a Boo House, the victim is able to flash light at the Boo to scare him away (when he is after their coins and stars). The Boo does not steal anything from the victim and the player ends up wasting 5 coins (to steal coins) or 50 coins (to steal a star) for nothing.
Gaddlights can be either bought or earned in boards in the game. The Gaddlight's main function is to ward off attacks from the Red Boo.
- The Gaddlight replaces the Boo Repellent from Mario Party 3.
- Even though the Gaddlight is created by E. Gadd, he doesn't appear in Mario Party 4 making his first appearance in a Mario Party game later in Mario Party 6.