Once upon a time, there's a magical river in the equestria girls world. until Sunset shimmer's foot touches the river, it turns into a fin! and then when her foot comes out of the river, she saw that it had turned into a fin before it turns back into her foot again! then, Sunset shimmer jumped in the river and she turned into a mermaid! She couldn't belive her eyes! she saw that she's a mermaid! And she can breathe in water, too! And then when Sunset shimmer jumped out of the water, she turns into a human again! She wants to let Twilight know about this. So, she wrote; "Dear princess Celestia, I found a magical water and it turns everybody into mermaids! and they can breathe in there, too! come join with me! Your friend, Sunset shimmer" and then Twilight accepted and went in the magic mirror. Join the underwater adventures with Twilight and her friends! if you're a manager, you can change the description and picture and add your own ideas to this studio.