In a moment of vindication, Percy boxed up the severed head of Medusa and shipped it off to Olympus, feeling like he was getting back at the gods for all their injustices. Seriously, because of his dad having a fling and Annabeth's mom being something of a bitch, he and his friends had nearly been turned to stone by the gorgon, and numerous other things had happened, like the bus being blown up, this stupid quest for Zeus' master bolt to avert a stupid war, his mom being killed by the Minotaur, the Minotaur existing in the first place, and hundreds, if not thousands, of other problems because of the gods.
So, sending Medusa's head off to Mount Olympus brought forth a tremendous feeling of satisfaction, like giving them a great big middle finger. Like, "This problem you guys created for me? Yeah, I fixed it. You can have your trash back now."
Did Percy have any kind of regrets or guilt about what he had done? Any concern about the consequences or potential ramifications? Nope. His mind was clouded by emotion right now, addling his better judgement.
"I wouldn't have done that," Grover said. "The gods will think you're impertinent."
"I am impertinent," Percy scoffed. He looked at Annabeth, daring her to say anything.
Instead, with a clenched jaw, she said, "Come on, we need to make a plan."
Leaving Medusa's lair and entering the New Jersey wilderness, the trio immediately appreciated how much trouble they were in: there, casually leaning against a tree, was a girl that looked their age, twelve. She had paper-pale skin, stunning auburn hair, and was wearing a pair of black jeans, combat boots, and a silver jacket. A bow and quiver were slung over her shoulder, and her very, very startling silver eyes were locked right onto Percy.
He gulped.
"M-Mistress Artemis," Grover stuttered. "What...what brings you-"
The goddess' silver eyes flicked to him, shutting him up, and she looked back at Percy, who was standing stock-still and sweating despite the cool temperature, the grip on his sword-Zoe's sword-so tight his knuckles were about to split his skin. Being a goddess and therefore not limited to human vision, Artemis had a perfect view of Annabeth despite not looking at her, and she saw how the girl was pale, could hear her panicked heartbeat, and could just see the gears in her head locked in place.
From behind her back, Artemis produced the box Percy had shipped to Olympus not even ten seconds ago. "This package has shown that your impertinence..." she trailed off for dramatic effect, "...show no bounds. You are to be punished for this, all three of you, for you, Annabeth and Grover, did next to nothing in halting Percy's transgression against the gods."
None of them said anything, all too scared to speak.
Artemis turned to her first victim. "Grover Underwood, keeper, physically twelve in human years, 35 in satyr years. You shall retain your duties and faculties, as you will need them."
She snapped her fingers, causing a silver wind to erupt around Grover, obscuring him from view. When the wind cleared, Grover was still there but he was totally different. His acne and facial hair were gone, leaving smooth skin. His Rasta cap was gone, and where his horns might've been were instead a pair of cat ears that twitched and moved. His jacket, hoodie, and jeans were gone, and in their place was a French maid's uniform, his legs now human, the fishnet stockings leading to a pair of high heels. Above his butt, in which he could feel something therein, under the bow of his apron, was a cat tail that waved around on its own. With trembling hands, Grover lifted the skirt of his uniform, revealing not only a lack of any underwear, but also a pink cage around satyrhood with no discernable lock.
"You shall be known as Grovette. You will be the sissy maid attendee of these two," Artemis said. "They're going to need attendance."
She snapped her fingers, this time engulfing Annabeth in the silver whirlwind. When it cleared, there wasn't anything visibly different about the blonde, but then there was a muffled sound that came from her backside, and the seat of her jeans promptly expanded, discoloring to brown on either side of the seam. Annabeth attempted to cry out, "What the Hades did you do to me!?" but what came out of her mouth was, "Gaga boo dah-bah."
She clamped her hands over mouth, her shock over her speech overriding the squishy mess in her pants for the time being.
"Annabeth Chase, daughter of Athena. You failed to use the voice of wisdom and reason your mother gave, therefore your punishment is to have no voice. Whenever you speak, all that will leave your mouth is the incoherent babble of a baby. A secondary punishment for your inaction is the loss of control of your bowels. You are to be a babbling panty-pooper." Artemis turned her silver gaze to Percy, making him squirm.
She snapped her fingers for the third and final time for this encounter, engulfing Percy in the swirling silver wind. When it cleared, he was the most altered of all, as his transgression was the most severe. However, Artemis was not totally cruel: it was all in his favorite color, after all.
Percy's hair had grown longer, and it was all pulled into a high ponytail held in place by a length of blue ribbon tied in a bow. In his mouth was a pacifier, also blue, with a design of a cartoon crescent moon on the button. A light blue onesie covered his body, a design on the chest taking the form of an oval with the words "Daddy's Princess" inscribed within. The onesie had puffy lace shoulders and lacy skirt. Around the onesie's waist was a length of blue cloth, tied in a bow at the back. Even with the onesie covering him up, it was obvious he was wearing a diaper, his front and butt being far too puffy for regular underwear, his legs too far apart. It was also clear that whatever diaper it was, wasn't Huggies or Pampers, but something special Artemis had cooked up.
Truthfully, the diaper was DC Idyl that she had shrank to fit the hips of a preteen boy, and the onesie was LittleForBig's "Daddy's Princess Lacy Dress" only with the color scheme altered.
There were no sexual additives to Percy's body, and his anatomy remained intact except for his hair, but other than that he was completely sissified. Something Artemis pointed out.
"You will now be called Priscilla. You will be referred to with female pronouns, and with think of yourself with female pronouns. Your diaper is not just for show, and you will be using it. Or using them, rather." Artemis produced a diaper bag and levitated it to Grovette. "As the sissy maid, it will be your job to interpret Annabeth's babel and change her dirty underwear, along with changing Priscilla's dirty diapers and making sure she gets her bottle every three hours."
Inside the diaper bag were more of the thick, blue DC Idyls, wipes, a changing mat, bottles, two extra onesies, extra pairs of jeans, and two packs of Disney Princess underwear, obviously intended for Annabeth and her future poopy accidents. It made more sense to Grovette for there to be pull-ups, not panties, but a punishment from a goddess was anything but practical.
"This is your punishment. Succeed and appease the gods, and it might be lifted."
A silver wind engulfed Artemis and she vanished, leaving Grovette, the plugged and caged sissy maid, Annabeth, the babbling and panty-pooping demigoddess, and Percy, the diapered sissy boy that just had to piss off the gods and bring this punishment down upon them all.
AN: At the moment, all of these stories are just standalone oneshots. This story in particular is based in part on "Curse of a Goddess" by Black Phoenix 7777 on Fanfiction. The baseline is that Artemis turns Percy into a girl for Medusa's head, and the story goes from there.
Go check it out yourself. Hasn't been updated in four years, but it's a good read.