Harpy
It was at this time that the villain MODOK came across her saw her condition and kidnapped and hypnotised her because he wanted to create a weapon powerful enough to defeat the Hulk, by subjecting her to gamma radiation, more than Bruce was subjected to, and transforms her into the insane and lethal Harpy creature.
The Harpy broke forward from a containment shell and immediately went after to the Hulk, so that she could destroy him. MODOK told the Harpy where to find the Hulk and she flew off in search of him, she first ambushes him and then the two of them fight each other to a standstill. Right when the Hulk is about to hit her while she's down, she tells him she's Betty, while Hulk is shocked and confused by her claim, she blasts him and knocks him out.
General Ross sees the Harpy and the Hulk fighting on TV and recognizes Harpy as his daughter Betty. He makes it to the battlesite and rushes to talk to her right before she blasts the Hulk, he trys to talk her down by telling her that she's a human being and that she's kind & gentle, and just when it seems to be working, MODOK's brainwashing start to take affect on her again, and finally she grabs the Hulk and flies away. Military jets take off after her but she manages to destroy one of them, before anything else can happen, a tornado appears out of nowhere and graps the Harpy and uncionscious Hulk, the tornado disappears and drops the two of them off on a city in the sky. The city is home to the the Bi-Beast, he steps out and reveals himself to them, after which both Harpy and Hulk attack him after he grabs the Harpy. The Bi-Beast manages to knock the Harpy unconscious and the Hulk reverts back to Bruce Banner, Bi-Beast tells Bruce he brought them there to keep him company but then asks Bruce to try and repair the machines that are slowly stopping which will cause his city to fall out of the sky. Bruce agrees to help, and since he doesn't know how Betty got turned into the Harpy, figures he can use the advanced equipment to help her at the same time. He goes to find the Bi-Beast and finds him trying to talk to the Harpy, who is trapped in a cage, Bruce says he'll help repair the equipment if the Bi-Beast lets him take the Harpy with him, to which Bi-Beast agrees. Bruce puts some equipment together which he thinks will cure Betty, but unbeknownst to him, MODOK came about the island and tricked the Bi-Beast into thinking Bruce was going to do him harm. The Bi-Beast attacks Bruce just as he hits the switch to start the equipment, after that a fight ensues as Bruce gets mad and becomes the Hulk and then MODOK doublecrosses the Bi-Beast and attacks him too. As the Bi-Beast hits the self-destruct button as a last resort, the Hulk turns back to Bruce and goes to search for Betty, he finds her in the eqiupment and she still hasn't turned back to normal, thinking that it didn't work, nevertheless he grabs her and they make a run for it as the island falls apart. Bruce as the Hulk rescues them both as they land, while at the same time parts of a building land on the Harpy as they run and when the dust clears, it is revealed that the Harpy has reverted back to Betty Ross showing that the equipment Bruce used was successful.
Read more about this topic: Betty Ross