A substance stored in an aerosol can used to repel both living and explosive and/or inflatable sharks. It is often found on bat-helicopters or whereever Batman thinks it would come in handy.
A battle where the two combatants place their hands above the head in an attempt to emulate the shark's top fin. The combatants then proceed to headbutt and bite each other while making shark sounds.
From the classic, campy Batman: The Movie starring Adam West. Robin (Burt Ward) had a habit of making strange exclamations (Holy Polaris, Holy Sardine, Holy Captain Nemo... you get the idea.
At one point in the movie, Batman is attacked by--you guessed it--an inflatable shark, against which he must defend himself whilst the faithful Robin runs to get the shark-repellent bat spray.
Should be exclaimed loudly and dramatically, for maximum campy effect.