
It's actually an Axolotl. I have no idea how to pronounce that. It's the larvae of a species of neotenic mole salamanders that fails to undergo metamorphosis. It's quite cool, really.
Axolotls are used extensively in scientific research due to their ability to regenerate most body parts, ease of breeding, and large embryos.But it may not be a Mudkip... it's actually more likely to be Wooper.

Ah, Pokemon steals once again from Mother Nature, because that's what fiction does.
-Joe.