Any pony race (earth pony/pegasus/unicorn/alicorn)
Feminine characters only.

Additional edits and/or linework changes are discussable only if the winning bid goes over $60.

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A little scene inspired by the picture:

A rumor was going across the village for a long while, long enough to transform into a local legend which nobody quite believed in, but still was getting slightly frightened by on every mention, deep inside.
The legend grew old enough to spread outside the village as visitors came and left, and even the villagers themselves, sometimes, were leaving their homes in pursuit of better lives. Them all were spreading the legend, one way or another, sooner than later, to the point of the village starting to attract adventurers from all over the land.
You are one of those brave persons, determined to either prove the legend being just a legend, or to face the dangers of that mysterious cave. For better or for worse, the entrance was completely open, clearly unvisited for a long while. Though some hoof marks could be seen here and there. You are not the first, you are not the last, you knew this beforehand, you knew that everyone that walked into this cave deep enough never returned. Yet, you keep going.
Eventually the quiet darkness ends, revealing a much larged section of the cavern system, with an opening on top with natural light coming through. In there you see a very dark, yet shiny...something. Something moving, something that makes weird noises, as its surface moved randomly... Something alive.
The pool of black substance seemed to have a life of its own, as you approached out of curiosity. The pool was ending in walls all around, leaving ony one way to get closer to it, a little natural stairs made of stone. As you get closer, you grow more curious. You want to touch it. Wait, what? Yes you do.
And so, you step in right away, seconds later you stand on both hooves in the black, thick and sticky substance. You feel the goo slowly starting to crawl up your legs but that wasn't your main concern at the moment - a figure, resembling one of your own kind, appeared from the pool, growing out of it, all made of that black substance. You get scared for a brief moment, you try to flee but your legs already were covered in goo up to the hips, with your hooves straight up submerged.
The black creature in front of you raises an arm as it extends into a tendril, starting to spin and swirl in for you to watch. And you do so. You keep watching. You keep staring. You keep staring. You want to touch it. You want to reach it. You want to touch that creature.
Your arm extends on its own, trying to reach the swirling tendril, while something latches to your back and pulls you away from the swirling beauty. It's so pretty. Such lovely swirls. You don't want to see anything else, you don't need anything else.
The goo keeps spreading all over your body, but you don't care anymore. All you see is the swirling tendril. You don't think of anything else, you want to reach it, you want to reach that pony-like creature to know it better. You want to stay here...and you will.