Aaron and Anna came to the tide flats and looked around. "There," said Anna, pointing at a glowing object, hovering in the water above a crater.
Aaron blinked. "Is that a … a starfish?"
And sure enough it was: a huge, glowing starfish, more than a foot across, was floating in place above the spot where it had fallen and landed.
As the two merfolk approached it, a soft and even kindly voice whispered in their heads, "I am the shooting starfish, and I have come to answer your wish. Speak, and it shall be done."
"Our wish?" asked Aaron. "Do we each get one, or … ?"
"I shall grant but ONE wish," said the voice, a little more harshly this time.
"We should stop and think about this," said Anna. "This is a big opportunity! We could really change things for the mer-village!"
"Yeah," said Aaron. "Seems like it'd be a total waste just to use a *wish* to make one or both of us human again. Hell, I don't think I even want to go back anymore. I just…" His voice trailed off.
Anna pressed him. "You just what?"
"Oh, it's nothing; I just wish—I mean, the only thing I really miss about being human is—"
Anna sighed. "The sex. It's sex, isn't it?"
Aaron nodded. "Yeah. I miss it. It's just not as good with a tail and fins."
Anna agreed. "Fish-sex is one downside of being a mermaid. The other is not being able to grow legs when I want to, so I can visit my family."
"Well I think that picks our wish for us then," said Aaron. "Let's just wish to give merfolk the ability to take human form at will—that would solve all our problems!"
"Oh, yeah!" said Anna, brightening. "That would!"
But the voice of the starfish spoke in their heads again, "This, I cannot do. While I have great power, including the ability to affect all merfolk everywhere in the world, my magic is of the sea and not the land."
Anna and Aaron both became despondent upon hearing this, and Anna asked, "You're saying you can't change any merfolk human, even if it's just sometimes or temporary?"
"Understand, little mermaid, there are Ancient Decrees that cannot be broke. Deep magic from the very dawn of time. I cannot contravene that which makes merfolk what they are. I can do nothing that would make you more like a land creature, more 'human' than you already are."
"Well shit," said Aaron. "So you can't give us legs?"
"I cannot."
"And how about if I wished … just hypothetically, what if I wished that all merfolk everywhere reproduced like mammals?"
"Yeah," cut in Anna, "like whales and dolphins, they're creatures of the sea!"
The great starfish was silent for a long while. It seemed to be … pondering. Or checking up on something. Hell, who could say? It was a magic talking starfish, after all.
At last, it answered: "This too would cross the Deep Magic. The Ancient Decree that makes merfolk what they are says you MUST remain fish from the waist down. This definition of your kind is magically inviolate, woven into the very being of the universe itself. It cannot be altered."
"God damn it," muttered Aaron.
But Anna was smiling. "Oh, is that all? We just have to stay fish below the waist?"
Aaron glanced her way. "What are you thinking?"
"Well there are still some kinds of fish that have sex!" said Anna. "Sharks. Guppies. Would you rather have two claspers growing out of your pelvic fins, or one gonopodium? Eh, wait, never mind—female sharks have a cloaca, that sounds gross. We should definitely go with guppy sex."
"I'm sure glad you know your fish biology, 'cuz I didn't get *any* of that," said Aaron.
"Just trust me," said Anna. She faced the starfish, spread out her arms, and wished, "I wish that all merfolk everywhere reproduced like a combination of guppy and shark, with internal fertilization that feels really good, sex organs similar to what guppies have, gestation like sharks—'cuz mermaids should definitely bear young in mermaids' purses, that only makes sense—and no fucking mating season, because that's bullshit!"
"Can you do that?" asked Aaron.
Once again, the starfish's voice was silent. Then, with a loud hum and a flash of light, the booming voice roared into their heads, "IT IS DONE!!! FAREWELL!"
Before they had time to celebrate, Aaron and Anna both doubled over in pain, as the organs inside the midsections of their tails suddenly rearranged themselves, and Aaron sprouted a new fin—just an unassuming little anal fin—right where his genital vent used to be.
The pain was sufficient that they both blacked out.