Heather Fox was a meteor infected activist with the ability to transform into the form of animals and the main antagonist in the Smallville Young Adult novel Animal Rage.
When Aunt Neil forces Lana to enter an oration contest sponsored by Lionel Luthor, Clark found himself caught up in the preparations. This quickly brought him into conflict with Heather Fox, an extremely single-minded animal rights activist who simply didn't get the necessities of occasionally killing animals.
Inspired to make her own nutrient drinks, Heather gathered vegetables from the greenhouse owned by Jodi Melville's family. Unknown to her as well, the vegetables were grown in soil with meteor rocks. As a result Heather was able to build up from her initial exposure to the meteorite shower, which had initially cured her of her allergies.
She gained control of her long-developing shape-shifting abilities, which allowed her to shape-shift into any live or dead animal she touched. However, while dealing with Heather's harassment in school is one thing, it's quite another when she discovers an ability to become any animal she touches.
Abusing her new powers, Heather stages a one woman terror spree against any she feels have wronged animals. But her attacks were becoming more violent, and she's losing more of herself to the beasts each time. Clark was presented with a genuine challenge for once.
Heather's attacks could injure him because of the meteor rocks in her system, and in nature, she had an almost limitless array of beasts to choose from. His method of dealing with her is clever, and at the same time, gives Lionel a much needed comeuppance.
Heather came across as both obnoxious and absurdly naive. She should have been aware of the necessities of farm life. As it was, her struggles against her rising animal natures were tearing her apart. Becoming what she hated, a killer of animals, was palpable. Her lack of integrity, when it surfaces involving a whippet, was a telling sign that she's not as holier than thou as she likes to believe.