In that POSSIBLE, not so distant future

Fluttershy: My dear Rainbow... you lack... vision. You want to turn people into mermaids out of leg envy and for the loss of your career as an athlete, as a runner. You are so short-sighted about this, my dear blue girlfriend.

Rainbow: Fluttershy... what has gotten into you?

Fluttershy: mmmmm..... determination... bravery.... and perhaps a bit of righteous cruelty. That's what has gotten into me. You see, my blue morsel... Mankind has been destroying nature for so long... and I will make them pay. I will sink their world, ship by ship, turn them into merpeople and make them clean up MY ocean, up to the last piece of plastic and trash.

Rainbow: Whoa, whoa girl, I am all in for ecology and nature, but you sound... totally like a villain. That's not cool at all!!!

Fluttershy: It was your stubbornness that made me use the ATTITUDINATOR to become brave enough stop you. You’re fighting so you can watch everyone around you become a mermaid and now regret it when you find somebody of your same species that not only puts you in your place, but will own you too. Think Rainbow, Think!

• Fluttershy makes a quick movement with her finger and snaps Rainbow's seashell bra bridge*
  

Fluttershy: Ah... much better. Now, girlfriend, join my army of sea creatures... or I will make Narwie here skewer you...

Part of a series of drawings for :iconannonmyous:, whose SFW versions will be uploaded here some time after being in my Patreon (this one has been up there since October)

This is a standalone, (as you guessed and as you know) part of the Equestria Girls series of My Little Pony, following my fan-story Equestria Mermaids.

:iconannonmyous: wanted to see how the girls would turn out if they became their evil selves from IDW's "Ponies of Dark Water" comic series

I thank you! Thank you! Thank you!