Original sketch as provided by  TransformationAnonymous.

"Lily, would you show me some magic?" asked Misty, her eyes sparkling with childish glee. "I've always loved magic, ever since I was a kid!"
"Sure," Lily answered with a sinister grin. "Let me show you my favorite spell!"
Before Misty had a chance to rethink her request, Lily waved her hands and spoke a quick incantation. She dropped to her hands and knees and vanished in a shower of sparkles. Where the tomboyish mermaid of Cerulean City had stood only moments before was a startled froakie, croaking in panic and surprise.
"I always loved the story of the froakie prince as a kid," Lily said. "I guess I'm just a romantic at heart."

---

So, I've never really been into pokemon tf much. Most pokemon, even the low-tier ones, are always somehow too cool to really hit the right notes that I enjoy in tf. But TFAnon was doing a pokemon themed stream where you'd get more chances if your tf was pokemon themed, so I decided to see if I coudn't come up with an idea I liked.
As a result, here we have an alternate timeline where Lily was a wicked witch instead of a friendly magician, utilizing tf spells on purpose for mischief, rather than by accident in the name of furthering human understanding. I was originally going to use Ash as a target, but I was having a hard time visualizing how Ash's hat would look good on a froakie, what with those huge eyes, and then I remembered that Misty originally asked to be shown magic first thing upon Lily's arrival. So, Misty became the target. Why does she still have her human clothes on? I don't know,, it seemed cartoony and fun. Sometimes I like to leave the TF victim wearing clothes that have changed to fit their new body.

I like this idea, honestly. I kinda want to refine it more and try to expand on the scenario a bit, but coming up next will be witchtober. I've got 3 out of the minimum 4 in my goal done. I've got the lineart for the fourth finished and a rough sketch on a possible fifth ready to go, but it was getting a bit exhausting to do multiple pics of the same character. Lesson learned; for next witchtober, any theme I use will not center around a single character. But I'll probably circle back around to wicked witch Lily at some future point.