You're a lizard that fell into a nuclear reactor, causing it to explode. The atomic energy caused you to grow massively in size and power. You were like Godzilla. You stood 400 feet tall, towering over the citizens of a major city as you began to wreak havoc as part of your revenge against humanity. You punch through buildings, crush cars underfoot, and shoot out a burning breath that burnt everything it touches. The military power couldn't stop you... your victory was almost guaranteed.
But then... a few hours into your rampage, you heard booming footsteps. You look around, thinking humanity has sent a giant robot, gorilla, or something to stop you. Nothing. Then, a gigantic shadow looms over you. You look up...
You see a giantess woman, and she has her massive bare foot raised above you. She's even more significant than you, standing over 10,000 feet tall! You're a tiny ant compared to her foot. You can hear the citizens below you cheer as they use her distraction as an opportunity to evacuate and run. She smiles heroically as she sees you stare up at her with uneasiness and as the citizens run away thanks to her.
"Do not fear everyone; your favorite giantess, Lady Earth, is here!" She preaches to the citizens, before looking back down at you. She's prepared for some collateral damage as long as she stops you. "Tough luck, lizard boy. Or should I say, bug boy? You're more like a tiny ant than a lizard compared to my feet! Did you really think you could hurt all these innocent people without someone stopping you? Think again. If there's anything I love more than helping people, it's squashing bad guys like you under my feet!"