Final answer:
Barbara Gordon was paralyzed after being shot by The Joker in 'Batman: The Killing Joke'. This event led her to become the character Oracle, aiding superheroes with intelligence and computer skills.
Step-by-step explanation:
Barbara Gordon, the original Batgirl, lost the use of her legs after an attack by The Joker. This encounter was depicted in the graphic novel 'Batman: The Killing Joke' by Alan Moore and Brian Bolland. In this storyline, The Joker shoots Barbara in the spine, which leads to her paralysis. The Joker's intent was to drive Commissioner Gordon insane by attacking his daughter and showing him photographs of the injured Barbara, hoping to prove that any ordinary person could go mad under extreme circumstances. Barbara's injury was a significant moment in Batman's history, leading her to eventually become Oracle, a key information broker and tech expert for the DC superhero community.