context: When Batman and Robin get a tip that Commodore Schmidlapp is in danger aboard his yacht, they launch a rescue mission using the batcopter. As Batman descends on the bat-ladder to land on the yacht it suddenly vanishes beneath him. He rises out of the sea with a shark attacking his leg. After Batman dislodges it with bat-shark repellant, the shark explodes. Batman and Robin head back to Commissioner Gordon's office, where they deduce that the tip was a set-up by the United Underworld, a gathering of four of the most powerful villains in Gotham City (Joker, Penguin, Riddler, and Catwoman).
  The United Underworld equip themselves with a dehydrator that can turn humans into dust (an invention of Schmidlapp, who is unaware he has been kidnapped), a submarine made to resemble a penguin, and their three pirate henchmen (Bluebeard, Morgan and Quetch). It is revealed the yacht was really a projection. When The Dynamic Duo return to a buoy concealing a projector, they are trapped on the buoy by a magnet and targeted by torpedoes. They use a radio-detonator to destroy two of the missiles, and a porpoise sacrifices itself to intercept the last one. Catwoman, disguised as Soviet journalist "Miss Kitka", helps the group kidnap Bruce Wayne and pretends to be kidnapped with him, as part of a plot to lure Batman and finish him off with another of Penguin's explosive animals (not knowing that Wayne is Batman's alter-ego). After Wayne escapes captivity, Penguin disguises himself as the Commodore and schemes his way into the Batcave along with five dehydrated henchmen. This plan fails when the henchmen unexpectedly disappear into antimatter once struck: Penguin mistakenly rehydrated them with toxic heavy water, used to recharge the Batcave's atomic pile.
  Ultimately the Duo are unable to prevent the kidnapping of the dehydrated United World Organization's Security Council. Giving chase in the batboat to retrieve them (and Miss Kitka, presumed by the duo as still captive), Robin uses a sonic charge weapon to disable Penguin's submarine and force it to surface, where a fist fight ensues. Although Batman and Robin win the fight, Batman is heartbroken to find out that his "true love" Miss Kitka is actually Catwoman when her mask falls off. Commodore Schmidlapp accidentally breaks the vials containing the powdered Council members, mixing them together.
  Batman sets to work, constructing an elaborate filter to separate the mingled dust. Robin asks him whether it might be in the world's best interests for them to alter the dust samples, so that humans can no longer harm one another. In response, Batman says that they cannot do so, reminding Robin of the fate of Penguin's henchmen and their tainted rehydration, and can only hope for people in general to learn to live together peacefully on their own.
  With the world watching, the Security Council is re-hydrated. All of the members are restored alive and well, continuing to squabble among themselves and totally oblivious of their surroundings, but each of them now speaks the language and displays the stereotypical mannerisms of a nation other than their own. Batman quietly expresses his sincere hope to Robin that this "mixing of minds" does more good than it does harm. The duo quietly leave United World Headquarters by climbing out of the window.
question: Who does Napier become?
answer: The Joker