From the Super Mario Wiki
Boo Repellent is an item found solely in the game Mario Party 3. It has a similar effect to Mario Party 4's Gaddlight.
When a Boo tries to steal coins or a Star from a player holding a Boo Repellent, the item automatically activates, spraying gas at Boo, causing it to flee. Boo Repellent can used only once. It is also possible for a player to throw away a Boo Repellent at the start of their turn to make room in their inventory, although it would count as using an item during user's turn.
Name in Other Languages
Tere yoke supurē