Changeling

Johnny Anything, "the Changeling" is a shape-shifter, a power mimic, and a sociopath. He can transform into any person or object he can see or imagine, and can use any super power is in close proximity. He is a foe of Jenny Everywhere.

His appearance is  irrelevant, as each time he faces Jenny Everywhere, he changes his appearance. Any and all artisitc renderings are accurate.

Origin
John "Johnny" Coleman was born a sociopath. He is also a very greedy person; anything he sees that he desires, he feels he deserves. And his parents were very rich people and gave him everything he asked for. The other kids at school called him Anything, since he was able to get anything he wanted. When he saw Jenny Everywhere use her powers, he wanted them for himself. He found that he could transform into her, and when he was around her, use her powers. He began using those powers to take whatever he wanted, and placed the blame on Jenny Everywhere. He even tried adopt her moniker, Shifter, though she called him Changling, and the name stuck.

Motivations
Johnny is simply motived by greed; whenever he sees something he wants, he takes it. He often tries to manipulate Jenny (in a form she will not recognize him in) to take somthing he wants, so as to shove the blame on her. Sometimes she sees through it, other times she doesn't, but each time she must fight him to retrieve the object of his desire and return it to it's rightful owner, absolving herself of his actions in the process.