A Pequena Sereia

Now, Ariel, I am warning you. Stay away from humans.

Now that you've had your 18th birthday, you can be contaminated and you will never be able to return to the city.

Father, what do you mean?

You see, from a male human sperm into a mermaid, our maid will become a human temporarily.

And if the mermaid follows us around, she's in danger of becoming human forever.