Sugar is one of the two tertiary antagonists of the movie Batman Forever, and one of Two-Face's love interests (and eventually the Riddler's minion), the other being Spice. She is played by Drew Barrymore.
Sugar is sweetness and light, and about as good as the good side of what Two-Face deserves. She is the exact opposite of Spice.
Near the end of the film, Sugar and the Riddler began a romantic relationship together. They discovered Batman's secret identity. She also helped him into his trap for the Dark Knight.
Not much is known about Sugar. Her real name is unknown, and she doesn't have an established backstory and it is unknown how she met Two-Face. It is also unknown what became of her after Two-Face's death, though it is likely she changed her ways or left Gotham before she gets arrested.
Not much was known about Sugar except that she was a love interest and henchwoman on Two-Face's good side while Spice was Two-Face's bad side. When The Riddler tracked them down at Two-Face's Hideout, he showed The Box to them and promised that he would help them solve "The greatest Riddle of all, the mother of all Riddles: who is Batman?" in return for helping him steal production capital and place boxes all over Gotham City.
They formed an alliance and hid out at Riddler's hideout at his factory that was called NygmaTech where Riddler developed a strong mind device to drain knowledge from the citizens of Gotham.
Sugar was Riddler's date (who was under his real identity of Edward Nygma) at the Ritz Gotham to help him show his new improved box to Gotham. When she saw Bruce Wayne (Nygma's ex-employer), Sugar said to Edward: "He is too cute. How come you don't look so good in that suit?" Edward was furious, and told her that she was there to work, not to stare at Bruce Wayne. She went with Edward to help him show the qualities of his new box that gave fully holographic fantasies. After he urged Bruce to try the machine himself, Edward danced with Bruce's date, Dr. Chase Meridian. Bruce went up to inspect the machine.
Sugar took the opportunity to follow Bruce, and asked him if he was looking for something. Bruce covered up his panic by telling her that he was just wondering how it could be turned off. She showed him by removing a green tube from the control panel. But while Bruce went in, Sugar secretly put another one in, which was what Edward had planned all along, in order to read Bruce's mind. After finding out from the Riddler and Two-Face that Bruce Wayne was Batman, Sugar became part of a trap for the Dark Knight. The Riddler invited Batman to Claw Island after he captured Chase and then Robin. Riddler told Batman that he knew who he was and if they could truly co-exist. Sugar suddenly appeared, pulled down a curtain on a glass cylinder, and revealed Chase. Then, Spice appeared, pulled down the curtain of the other one, and revealed Robin. The Riddler gave Batman a choice to rescue Chase or Robin, but Batman distracted him by giving him a riddle of his own long enough for him to destroy the mind device, which warped the Riddler's mind in the process.
As Riddler's Lair exploded around them, Sugar and Spice escaped. What happened to them both after that was unknown, but the novelization said that they disappeared from Gotham forever to avoid capture, while Two-Face was killed and Riddler was taken to Arkham Asylum and was declared insane.