Misty

As Ash left to test his remote, he ended up running into his old partner Misty.

"Hey, Ash!" Misty giggled. "It's been a long time."

Ash was speechless for a while. Misty had grown into her body. Her legs were longer, and the overalls that connected her pants and shirt seemed ready to burst. Her cleavage had gotten bigger as well.

"Hi, Misty." Ash said. "You still running the Gym?"

Misty nodded. "Yeah, although my sisters are still the technical Gym Leaders."

Ash hit the pause button and drank in his old friend's form. She was the perfect first test subject.