what you need: cup of water , piece of jewelry
take a piece of jewelry and put it in the water. And then focus on you being a mermaid and the color tail and powers you want. And say this only one time.
''Twists and twirls of the sea. Can you speak to me? Grant me to be a H2O living creature. I would like powers to protect the sea so mote and make this me I'd like a shiny tail since I'm a girl so make this me. I live as a mermaid, let it be because I invoke thee. Sea living objects will you make this me? This is who I wish to be. Please make me what I deserve to be, a human like fish is me. So Mote Me Be.
I'd have the tail the color () and thy power () please this is all I need to protect myself and the sea. Sea belongs, human does not. I'm free to be no longer inside humanity. SO MOTE IT BE. I grant a wish of the sea. So make this me MOTE JUST THIS ONE FOR ME!!!''