Not that this is a bad thing - the snaky half gives some real world link to the swallowing their prey whole bit, and their noodle-like bodies are just a treat for anyone higher up the food chain. However, I wanted to add my little twist to this second part by moving down the evolutionary ladder to a worm-girl; more specifically a tapeworm-girl.
This would make great willing prey since her real life, parasitic counterpart actually gains nutrients from its host's bowels and is immune to gastric acids... not to mention that she would look cute as heck with a raggedy hairdo made up of latching spikes.
As much as I'd like to put my money where my mouth is, I have neither the skills nor currency to give this concept any form.
So...erm...there you have it. Free idea for a new OC.
P.S. Feel free to stop me if this has been done already...