This is one of my characters, InK the Toxique. She was heavily modded by me using pieces from EVERYWHERE, including ones I made myself. Today/yesterday I finally updated her and gave her a mesh body, which completes her goopy, flowing oil look.

She was heavily inspired by the character Inque from Batman Beyond, so much so that she's got the same abilities and weaknesses, except her origins are different.

InK came from a zone that was flooded with toxic waste by Robotnik/Eggman. There was no experiment involved, she just crawled out of a particularly large pool of poisonous sludge and stepped out into the world. Her true form is a black puddle of oily goop, and she can change herself into any shape and form she desires, which happens to look like the monstrous one you see here. (Toxique is her title, and Toxiques are usually beings born from toxic waste like she was.)

She took on a job as a mercenary; she doesn't really need money for anything, she just enjoys destroying things, killing and ruining the days of others... The cash is just an added bonus.

InK has no qualms about seducing her prey to get what she wants, and that's usually just to reel them in before she delivers the killing blow. She may appear shameless to some, but that's something that should be feared.

Like Inque, she's extremely weak to water and ice; these things can separate her molecules or freeze them and that's not really something she wants. Water can wash away filth, and she'd rather stay around to make a mess.

Feel free to be charmed by her, but you might not want to get too affectionate with her-- she IS VERY toxic to organic beings.

I imagine her being voiced by Miss Fortune from League of Legends.
Her theme song is "Toxic" by Britney Spears