Bat Shark Repellent
From HallsWiki
Popularized in Batman: The Movie, Bat Shark Repellent is Batman's trademarked tool for dissuading shark attacks. Simply spray, and the shark falls off. The repellent made it to the semi-finals of the Battle to End All Battles II. Whenever it is mentioned in the Halls, the customary response is to point out that there is no such thing as a Bat Shark.
