Somewhere in the DC multiverse...

Lex Luthor's scientists had finally completed his newest device.  During a meteor shower three months prior, an asteroid the size of a small building fell into the Pacific Ocean.  It contained rich deposits of kryptonite inside.  Luthor paid for an expedition to retrieve the kryptonite and bring it to his labs in Metropolis.  Luthor had been working on a device, powered by kryptonite radiation, that would be able to amplify the powers of any super powered individual.  He decided a ring would be the best tool to house the device and spent the last couple months working on a prototype, which was now complete.  He needed a guinea pig to help test the device.

Giganta had been down on her luck since Darkseid's failed invasion of Earth had left many villians and heroes alike dead.  Gorilla Grodd was missing, presumed dead and without him Giganta had taken to doing small robberies here and there with Harley Quinn, who she shared an apartment with.  So, she was excited to receive a call from Lex Luthor about joining a super team.

She met Luthor at his Metropolis LexCorp office where he offered her the device in return for being on the team.  Giganta happily jumped at the idea, she'd have a device powerful enough to make her many times larger than she would normally be able to grow.  Luthor walked her to the lobby where he gave her the ring and suggested that she might cause some trouble in Metropolis as Superman would be a good adversary to test the device against.

Giganta: "but I've never been able to beat Superman"

Luthor: "trust me Giganta, you've got kryptonite, it should be easy and if you fail I have enough resources to get you out of jail"

With that Giganta left LexCorp and Luthor smiled to himself.  He had the perfect plan to beat Superman and take over the world this time.  Giganta would be that tool and he would control her, if needed.

Half an hour later and several miles away from Luthor's LexCorp building, Giganta grew a bit bigger than her normal height, due to the ring, and started stomping around the streets of Metropolis.  Citizens were running in all directions away from her.  Bruce Wayne was having lunch with the owners of other technology companies a few blocks away.  Wayne Enterprises was looking to expand in Metropolis and Bruce was looking to get a lay of the land from fellow business owners.  As people were seen running in panic, Bruce excused himself and found a proper location to change into Batman.  At the same time, Clark Kent was working on a story across town for the Daily Planet.  News came in quickly about what Giganta was doing.  He quickly changed into Superman and flew to the scene.

Superman and Batman arrived at roughly the same time to find Giganta stomping about.  She looked down and saw the heroes gathered on the ground.

"ABOUT TIME YOU GOT HERE SUPERMAN," Giganta said looking down at him, her right foot lifted ready to stomp him.

"I don't know what you thought you'd accomplish, but it's over," Superman said as he prepared to fly up to Giganta ready to hit her.

As Superman flew passed Giganta's foot she curled her toes, revealing the kryptonite ring around her 2nd biggest toe.  Superman immediately felt weak, his eyes rolled back, and he clenched his stomach with pain.  He stopped flying and fell to the ground in pain.

"AWW, DID ITTY BITTY SUPERMAN GET A LOOK AT MY NEW TOE RING," Giganta said mockingly.

Giganta lowered her foot on Superman, smothering him beneath her soft sole.

"OH SUPERMAN, YOU FEEL GOOD UNDER MY FOOT," Giganta said, continuing to mock Superman.

Batman was taken aback by the events and had no time to react as Giganta quickly put her foot on his fellow Justice League member.

From beneatch Giganta's sole Superman lay flat, too weak to fight against Giganta's foot.  The kryptonite was still close by and Giganta had placed most of her weight on him.

Suddenly, Giganta felt raw energy corsing through her, somehow the close proximity to a super powered individual was charging the ring, making it more powerful.  She tried growing again and found herself growing to heights she'd never experienced.  She was now several hundred feet tall.  She increased her weight on Superman, who was now powerless to the whims of Giganta's sole.

"YOU WON'T BEAT ME THIS TIME SUPERMAN," Giganta laughed as she lifted her foot.

She then saw Batman attempting to flee, no doubt wanting to retreat instead of attempting to fight someone hundreds times bigger than him who had just taken out the Justice League's strongest member.  However, Batman did not get far as Giganta simply lifted her foot, pivoted and brought her foot down, catching Batman under her heel.

"TWO HEROES UNDER ONE FOOT, Giganta mocked down to the defeated duo.

Giganta stood for a few moments bending to look at her feet.  She'd done it, in just a few moments she'd defeated two heroes that stopped her for years.

"IF I WERE YOU TWO I'D GET USED TO THAT POSITION," Giganta said dominantly.

She then lifted her foot and peeled Batman off the bottom of her heel.  Batman was unconscious and put no effort to fighting Giganta's fingers.  'Batman's costume must be incredibly strong to withstand my weight at this size' Giganta thought to herself.  She had no intention of killing Batman and held him in her hand as she shrank down to her normal height.  After returning to her normal height she was surprised to see that Batman had also shrunk with her.  'Do I have the power to shrink people now?' Giganta wondered.  At the same time, Superman was still under her sole, but shrunk down just as Batman was.  'I wonder if I have any more powers' Giganta thought to herself.  She tried to levitate and found herself able to do so, then took flight.  She left Metropolis and headed back to her apartment.  She knew that other members of the Justice League would be on their way if she stayed in Metropolis and with both Batman and Superman defeated and at her mercy there was no reason to stick around.  She would contact Luthor later and see what his plans were.