Author's Notes:

I wrote this after my second story. Its quality will probably still be inferior so try not to expect too much from it. If it seems a little unlikely, try not to take it too seriously either, I just do what I have to do to get the scenarios to work. I'm not sure if all the hate for Starlight will make people want to see this happen to her or whether she'd be a turn-off, but here we go.

Also, I considered a darker ending, touched upon in the second last paragraph, but decided against it because I don't want to torture the ponies too much, not even Starlight.

Starlight Glimmer was trying on an outfit made by Rarity. It was a skintight dark purple outfit.

"You look smashing," said Rarity, who was wearing a cute pink miniskirt (seen in the episode Sleepless in Ponyville). "I'd say you're ready for my fashion show tomorrow!"

"What if she tries to crash it?" said Starlight.

"Then you blast her as hard as you can!" said Rarity. A sudden urge hit her. "I'll be right back. I need to use the little filly's room." Rarity walked toward the bathroom of Carousel Boutique. As she was opening the bathroom door, a sewing machine suddenly levitated and hit Rarity in the head, knocking her out.

About a minute later, Rarity returned.

"Where's your outfit?" said Starlight.

"I took it off for now," said Rarity. "Hmmm. Maybe you should wear that outfit over there."

Starlight turned in the direction Rarity was looking, and a few seconds later, suddenly blacked out.

Rarity woke up. She was still laying next to the bathroom door. After rubbing her head, she immediately sat up in horror. Her pink dress was wet and she was sitting in a puddle. She had peed herself when the sewing machine had knocked her out. Rarity blushed with embarrassment. This was the third time! She ran into the bathroom to shower, hoping Starlight wouldn't find out, although she'd have a hard time explaining to Starlight why she suddenly decided to take a shower.

...

Starlight woke up inside a cave. Her hooves were glued to the ground with green slime, and she also had some on her horn, preventing her from using magic. She knew who had to be behind this.

Rarity walked out from behind a corner. "Ah, Starlight Glimmer. Awake, I see." In a burst of green magic, she transformed into Queen Chrysalis.

"What did you do with Rarity?" said Starlight.

"She's fine," said Chrysalis. "Aside from wetting her outfit for the fashion show. Which gave me an idea as to the first step of my revenge on you!"

"You wouldn't dare!" said Starlight.

"Wouldn't I?" said Chrysalis. She levitated a potion. "I prepared this potion that any pony who drinks it will have to pee so badly it's as if they drank 20 glasses of water!"

"Where do you even get a potion like that?"

"From Zecora. When I was spying on your friends, I saw Rainbow Dash ask Zecora to make a potion like this. All I had to do was change into her and ask Zecora for one after I trapped you here!"

"Why would Rainbow Dash want this potion?"

Chrysalis paused. Rainbow Dash had told Zecora she wanted to practice holding it for longer, but Chrysalis had noticed her blush lightly and sweat profusely when she said this. So she had followed Rainbow Dash for a while and seen her drink the potion and then pee in her Equestria Games outfit. She considered telling Starlight Rainbow's darkest secret, but figured that the knowledge that one of her friends actually enjoyed peeing herself might make Starlight feel less ashamed of what was to come, and her beef was with Starlight more than Rainbow Dash. "She wanted to use it for pranks. And now I'm using it for vengeance!"

Starlight tried to blast Chrysalis with her magic, but the slime on her horn did its job. She was powerless. Chrysalis put one of her hooves on Starlight's nose, opened her mouth with the other hoof, and forced her to drink the potion.

Chrysalis sat on a makeshift throne, sipping wine from a goblet as she waited patiently for the potion to take effect. After about ten minutes, Starlight was already fidgeting. She hadn't needed to go this badly since as long as she could remember.

Chrysalis licked her lips as she watched Starlight squirm. It was because of her that her army had betrayed her for the traitor, Thorax. Watching Starlight suffer gave her more pleasure than Shining Armor's love for Princess Cadence.

"You don't have to do this!" said Starlight, desperately trying to hold it in, which was difficult with all four of her hooves trapped, unable to even cross her legs. "Please, set your vengeance aside and change your ways, like I did!"

"This is only the beginning," said Chrysalis. "I have far worse surprises in store for you once this is over!"

As Chrysalis described vividly some of the things she intended to do to Starlight, Starlight felt a bit of pee leak into her outfit, though she was able to hold the rest of it in and tried not to listen to what Chrysalis was saying.

"And that will teach you to defy me, the queen of the changelings!" said Chrysalis.

Chrysalis waited for another half hour. Starlight really needed to go.

"Can't you just let me go now and seek the rest of your revenge later?" said Starlight, tearing up from the strain of holding it in.

"I want you to suffer as much as possible!" said Chrysalis.

"I can't... hold it... any longer..." Starlight felt the crotch of her skintight outfit grow warm and wet as she began peeing. She blushed, tears streaming down her face while Chrysalis licked her lips, savoring every moment. Starlight felt the wetness soak the legs of her outfit. She peed for about a minute, feeling more embarrassed by the second as the puddle under her grew bigger and bigger.

"Revenge is so sweet," said Chrysalis with immense satisfaction as Starlight finished peeing herself. "I'll let you go for now. I want you to live with the shame of wetting yourself for a while yet before I kill you." With a blast of magic, she destroyed the slime on Starlight's hooves, but not her horn. She knew Starlight would try to blast her as soon as her horn was free. Chrysalis flew away laughing maniacally.

Starlight walked out of the cave. She recognized the area, and made her way towards Ponyville as slowly as she could. Then she saw a small pool of water, and jumped into it. She'd just tell Rarity that she'd escaped Chrysalis's cave through a river. She suddenly remembered that Chrysalis had said she'd made Rarity wet herself. Feeling slightly less ashamed of her accident, Starlight decided to pretend to Rarity that Chrysalis had said nothing about it. Rarity would feel better about it if she thought no one else knew.

Chrysalis watched through her crystal ball. "Damn it!" she said. "I should have turned into Celestia and dropped her off at Twilight's castle to make sure every pony saw! No matter. I'll have to remember to mention it next time we meet!"

...

Rarity finished washing her outfit. It was sparkling clean and would be ready for the fashion show tomorrow. She wasn't sure where Starlight had gone, and hoped Chrysalis hadn't gotten her foul hooves on her. Great was her relief when Starlight returned and told her story to Rarity. She was just as relieved that Starlight seemed unaware of her accident when Chrysalis had attacked her. It was bad enough that Twilight and Applejack had already seen her wet herself - although somehow she felt much less ashamed of the instance with Applejack. She hung up Starlight's outfit to dry next to her own.