What kind of thing is he?

Her head is similar to that of an axolotl, her body is bipedal like a human and she has a long tail disguised to look like a common leaf. I'd imagine her skin to be somewhat rubbery but still soft, and her slightly segmented "horns" to be made of chitin with a very thin layer of goop. She's also an absolute amphibian meaning she's capable of being on both land and water indefinitely, although her skin would become slightly crumbly when exposed to air for too long.

To put it briefly: she's like an axolotl with humanoid features and a leafy tail.

nice