Susan Maguire was a mysterious woman who quickly infatuated Bruce Wayne, but turned out to be a plant creature loyal to Poison Ivy. The flora-wife of Bruce Wayne, Susan was a creation of Poison Ivy. Done so that Ivy's plant people could inherit the fortunes of their now deceased wealthy spouses, dozens of couples got married only to be deceived on a cruise they all later took. Batman, Robin and Batgirl discovered this plot and destroyed all of the plant drones.
Bruce met Susan at Veronica Vreeland's wedding, where she was ostensibly a friend of the groom, Michael. The two began dating, and Bruce found the more time he spent with her, the happier he felt. She seemed perfect in all respects, and even seemed to diminish the pain of loss of his parents. After a short courtship, Bruce proposed to Susan and she became his wife. As an added decision, Bruce decided to give up his Batman identity. Although Tim Drake and Barbara Gordon were happy for Bruce, Dick Grayson remained suspicious of Susan, and completely disbelieved that Bruce would be capable of giving up his life as Batman.
Dick was proven correct on both parts. During their honeymoon, Bruce discovered that Susan was secretly one of Poison Ivy's creations. At the same time Batgirl and Robin had discovered that Ivy was creating "perfect" mates for rich socialites, who would then kill their spouses and inherit their fortunes. The duo made their way to the honeymoon cruise carrying Bruce and several of these socialites, and aided him in overcoming the other plant creations and evacuating the innocent passengers to safety. Susan, whom Bruce had locked in their stateroom, was last seen gazing out the porthole as the ship sank, and she was destroyed.
Her marriage to Bruce was presumably annulled.