Giganta starts out as Doctor Doris Zuel, who worked at a medical facility where the comatose Wonder Woman was being kept. Dying of a terminal illness, Dr. Zuel plotted to transfer her mind into Wonder Woman 's body. This procedure was stopped halfway by Wonder Girl and both Dr. Zuel and Wonder Woman were declared dead. Neither of them were, however.
Dr. Zuel's assistant found out that her essence had been stored in the transference machine's buffer module. Wishing to save her, he put her in the body of one of the test animals, a gorilla named Giganta.
Dr. Zuel was not pleased with this, desiring a human body. She discovered another suitable host: a beautiful red-haired strong woman from a traveling circus named Olga, who was comatose. Absconding with Olga's prone form, Zuel did another transfer, successfully putting her mind in Olga's body and, presumably, Olga's mind into the gorilla. (That being said, the fate of Olga and the gorilla have never been revealed.)
Dr. Zuel discovered something amazing. She could now grow to a gigantic size, a power that Olga had possessed before Dr. Zuel stole her body. Using this ability, Dr. Zuel, now embracing the identity 'Giganta', joined Villainy Inc., but met with defeat at the hands of Wonder Woman. She would later on join Secret Society of Super Villains, a united team of super villains.
After Donna Troy assumed the identity of Wonder Woman, Giganta teamed up with the Cheetah and Dr. Psycho to search for the 'real' Wonder Woman, Diana. After holding Donna hostage, they eventually clash with Wonder Girl, Robin, Hercules and Diana, who was under the guise of Diana Prince, government agent. Giganta is ultimately defeated by Hercules in this conflict.
Giganta's next appearance featured her as an instructor at Ivy Town's University, but under the control of M'Nagalah, the Cancer God. Under his influence, she was assigned to seduce and capture the new Atom, Ryan Choi. She ended up swallowing him whole but he managed to escape by making her sick, thus causing her to cough him up.
Free of the M'Nagalah's control, Dr. Zuel remained in her position at the university. She has also since approached Ryan for a second chance, despite the unusual nature of their initial encounter.
The two do make a second date, but before it happens Ryan is asked by Wonder Woman, on behalf of the Department of Metahuman Affairs, to wear a wire on his date with Doris. During their date, Doris discusses her desire to reform. When Ryan is away, however, she learns that he was wearing a wire and angrily tears off the roof of the restaurant to see Ryan and Wonder Woman talking, unaware that he had removed his wire. Wonder Woman and Giganta fight, with Wonder Woman emerging victorious. Ryan intervenes, preventing Wonder Woman from beating her further. Wonder Woman admits she lost her temper, but both realize that Giganta had escaped. It is unknown whether or not Doris heard Ryan's pleading on her behalf.
Giganta has appeared as one of the inmates on the prison planted in Salvation Run. As part of the group that follows the Joker, she has apparently formed a friendship with Leather. Giganta was seen as a Member of Libra's SSSV, and at the end of Final Crisis #3 she is shown as a Thrall of Darkseid alongside several other Super-Powered Women. She is now called Gigantrix and wears a mask with a skull and cross bones design. Giganta was being controlled at this time by a Fury and this control was maintained by the mask, until Supergirl destroyed it which resulted in Giganta being released from Darkseid's control. She was recently hired by Secret Six to aid them while their teammate Catman was away. She would join a Secret Six version who would battle the current version of the Secret Six. She returned stateside with the others and Amanda Waller had them all pardoned by the President. She tells them that the Suicide Squad is not seen in a positive light and that she needs 6 members to be called upon for secret missions. She invites Dwarfstar to her room. When he shuts the door she begins to beat him and torture him with his own molecular belt. She tells him that he killed her boyfriend Ryan. She duct-tapes his mouth shut before killing him. He begs for his life, in contrast to Ryan Choi who did not when facing overwhelming odds against Deathstroke's Titans.