King of the castle
Bowser has a very important meeting and nothing is allowed to go wrong. Which means it’s a very bad day for Shade to try out a voodoo doll and get revenge by dishing out some punishment.
Bowser adjusted his tie. It felt suffocating, but he had promised his henchmen that he would put in the effort today. They had gone through the effort of getting two Toads to agree to travel all the way from Mushroom Kingdom. They had decked out the largest conference room with the most expensive tapestries and the most luxurious torches, inlaid with gold and rubies.
They had even drained the lava away for the occasion. They had said it looked too intimidating, which Bowser thought was ridiculous. There was nothing more refreshing than a quick lava bath to get the blood pumping. Lava was not intimidating. It was home. Just like being naked showed how comfortable Bowser was around people. Just like roaring loudly showed his excitement. 
And Bowser understood that the Mushroom Kingdom had other customs. He did. He knew that his best chance of making gains was to wear a suit and play the part in order to earn their respect. But none of that meant that he had to like it.
“The Koopa Troop is the only reason that there is still a region to defend!” Count Bleck said. Bowser’s loyal lieutenant was getting more agitated by the second.
“While Princess Peach appreciates the assistance,” Left Toad said, “we have tried mobilising our own troops multiple times to help protect against the wildlife threat. Which has been blocked by the Koopa Troop at every turn.”
“We have defended the area for two years now.” King Boo said. “We’re not going to risk the safety of the civilians because your stubbornness insists that your clique of incompetents get a crack at it.”
“Calm!” Bowser ordered. 
The room silenced itself, exactly as it should. All eyes were on Bowser. He indicated for Antasma to speak.
“We have a stake on the land by right of assistance and we are merely requesting that you acknowledge it without sending in your troops every few weeks.”
“The land is ours.” Right Toad said. “And if your leader would stop being so childish, he would admit to it.”
“I’m not a child.” Bowser glared at the toads. “I’m a baby.”
Silence descended on them again. Bowser’s cheeks flushed. Because it was impossible that he had just said those words. He coughed to hide the slip-up.
“Excuse me?”
“I’m a Maybe.” Bowser improvised. “Were you not briefed on Koopa culture, you imbecile? A Maybe is an adult who could maybe be considered one of the elders of his tribe. Were you not properly briefed by Princess Peach? Did she send mushrooms barely out of their spore state to talk to me?”
The Toads looked at each other. “No… no, Bowser sir. We simply misheard.”
Bowser glared at the rest of his army, daring them to contradict him. 
~*~
Shade could barely contain his giggling. It had worked! It had actually worked! He had hoped it would, of course. And then his first test had been a resounding success! He had camped out on a railing at the top of the room, his newly acquired voodoo doll sitting peacefully in front of him, while Shade had a perfect view of the conference below him. He could hear every word, which had been mind-numbingly boring until Shade had stepped in to spice things up.
The voodoo doll was a Bowser plushie that had been enchanted to link to the king of all Koopa himself. Shade had found it a while ago and had been saving it for a special occasion. 
The Koopa wiggled with excitement, only to wince at the burning reminder that his padded backside was still hurting from yesterday’s punishment. Bowser had been so unfair to him, just because Shade had been playing a little too roughly and some supposedly priceless artifacts had been destroyed when he had bumped into them. It wasn’t Shade’s fault that those things were kept around unsupervised and far too close to his designated playing area.
Just for having a little fun, Shade had been pulled over Bowser’s lap, had been called a baby, and had been put back into diapers for two whole weeks. Shade didn’t need diapers! He only rarely had accidents.
But, well, if Shade was going to be treated like a baby for having a little fun, Bowser deserved to be treated like a baby for being unfair.
And Shade had just the perfect voodoo doll and box of toys to make that happen.
~*~
Left Toad still looked sceptical. “Even if you’re one of these ‘Maybes’, that doesn’t mean your behaviour is any more mature. The land belongs to us and you can’t just put your paws on it and yell ‘finders keepers’. That is not how international law works.”
They were all looking to Bowser. He tried to go over the ways to get the respect back he was entitled to. The legal arguments were complicated and he had his henchmen for that. What he needed to do was show who the ruler of the Koopa Troops was and how he had earned his way to that position.
He stood up firmly, preparing his deadliest glare. He would have to do a power move. He had enough to choose from. And then he opened his mouth to remind the ambassadors just how much mortal peril they were in if Bowser decided to dislike them, but there was no time to speak the words. Because right in front of his face there was a sparkle of magic and an item appearing out of nowhere. And that item was a pacifier.
Bowser looked to all his lackeys, studying them all to see which one could have summoned it and for what reason. Until suddenly that pacifier shot towards Bowser’s mouth and entered it.
Bowser’s face turned crimson. Around the table, his henchmen were snickering. They were relaxed to the point of insubordination, like this was a simple prank Bowser was subjected to. Bowser pulled on the pacifier to remove it, but it wouldn’t budge. It was stuck in his mouth, where he was even forced to suck on it. 
“Whoever ish doing thish, shtop ith!” Bowser lisped angrily around him. He stomped the ground, trying to interrupt whatever magic spell was being cast. But to no avail. The pacifier was staying in.
And suddenly the stomping was not making any more noise. Because Bowser’s foot wasn’t reaching the ground. Both his feet were lifting up into the air, because his whole body was hovering like a common boo.
In front of Bowser appeared a white rectangle. And it was hard to tell what it was at first. Because Bowser had never seen one in that size. But it was a diaper. And the magic was going to put him in it.
“No!” Bowser yelled through the pacifier, struggling even more than before.
But there was nothing he could do as his clothes slipped off him one by one, tossed aside until he was left in his birthday suit. Something that should make him more comfortable any other day, but was now a clear sign that the magic was ready to move on to the unspeakable next step.
“Stop!”
“Don’t get too worked up, sir.” King Boo snickered. “You might have an accident before the diaper’s put on.”
“Shuddup!” Bowser shouted through the pacifier.
The diaper seemed to think that was its chance. It rushed towards bowser’s body and unfolded. It wrapped around Bowser’s crotch and loudly taped itself tightly against Boswer’s body. Bowser had not worn one of these since he had been a baby. It was far thicker than it had any right being. Far softer and more comfortable too.
Bowser’s face burned red and he didn’t even have the control over his own body to hide his face behind his paws. “Guards! Figure out who’s doing this and stop it!”
“I’m thinking he likes the humiliation.” Left Toad said.
“Oh definitely.” Right Toad said. “This is probably how he dresses all the time in private.”
Bowser fumed. He opened his mouth to yell, but his lips were still wrapped around the pacifier. His throat wouldn’t obey him. The words that were coming were not the ones he had been meaning to say. “Of course I do. I love my big poofy diapers.” Bowser almost bit his tongue trying to stop the words from coming. “I’m such a big baby and everyone should know it!”
“I’ll draw up the announcement today.” Antasma said with a smirk.
“I’m not saying this willingly, idiot!” Bowser snarled. He looked around. But there really was nobody at the table casting spells. Around him perhaps? He couldn’t see anything in the room.
“It’s just so hard to see what you’re wearing and not come to the conclusion you’re just a baby.” Left Toad said.
“A big baby.” Right Toad agreed.
“I’m not a baby!” Bowser yelled. 
There were sparkles in front of him and suddenly a splosh of red fabric. It was a onesie. And it had the text ‘I am a big baby’ written on its front. Bowser thrashed with his arms, but the onesie was coming for him without escape. Bowser’s arms were suddenly out of his control, forced to raise up and be fitted into the garment. The onesie slotted into space and buttoned shut over the diaper.
As soon as Bowser could move his arms again, he moved his paw down to undo the snaps and get the humiliating garment away from him. He managed to undo one snap before his arms were forcefully raised above his head again. The snap was redone and there was another flash of magic. Thick red mittens appeared and moved to cover Bowser’s paws, strapping themselves locked.
This time when Bowser had control over his arms again, he found it impossible to undo any of the onesie’s snaps. He was so distracted by the attempts, that he hardly noticed another flash of magic, another bit of red fabric, which found its way to his feet and further dressed him. Thick booties, looking far softer than anything Bowser had ever worn before in his life.
At least the magic finally stopped levitating him. Bowser was lowered to the ground, fully motion to glare at the assembled group who were hiding their faces with their paws. Presumably to hide the giggling, but Bowser could hear that anyway.
“This will be quiet a memorable visit.” Left Toad said. “We even got our own personal show.”
“Yes.” Right Toad said. “We’ll be sure to give the princess a full in-depth report of your exceptional hospitality.”
Bowser stomped to put some fear in the guests. Except when his foot hit the ground, there was a squeaking sound. His little booties made squeaking noises when pressed. No. 
Bowser wanted to sink through the ground. “How has nobody figured out the source of this yet?!” He shouted to his guards.
“Probably just a manifestation of your deepest fantasies.” Left Toad whispered just loud enough that everyone in the room could hear.
The guards looked at each other uneasily. “We’re searching high and low, sir. Normally we’d invite the court wizards to help investigate.”
“What’s stopping you?”
“They’d have to come and see you like this.” The guard responded.
Bowser took a step towards him and he had to waddle. Because he had a diaper between his legs that was so thick that it was keeping his legs apart. The guard who tried to divert his eyes to keep from reading the text on Bowser’s onesie, or notice the red mittens or booties. Of course Bowser didn’t want anyone else to see him like this. But it had to be stopped before it could get any worse.
Except, what was Bowser thinking? It couldn’t get any worse than this.
“Fine! I’ll search for them myself then!” Bowser tried to storm off. He really did. Just a short walkway until he would have made it to a hallway and out of sight of these dignitaries. Just a small sprint to escape the humiliation.
But the magic wouldn’t let him. The moment he had made it a few steps away, Bowser could feel himself levitating again. The pacifier moved out of his mouth and Bowser smiled at the small mercy. Finally he could complain about this predicament without sounding like a damned infant.
Except the magic had other ideas. Because there was a flash of sparkly magic and then something white. A glass bottle filled with milk.
Hell no.
Bowser fidgeted and thrashed, but there was no helping it. His violent movements were turned into slow rocking from side to side, and the bottle went into his muzzle. Bowser shook his head, tried to get away. But then his mouth started working on its own, sucking on the bottle’s teat in excruciatingly loud smacking.
The milk was nice. Bowser had assumed, from the nature of the rest of his treatment, that it wouldn’t be. But it tasted fresh and warm and comforting. It made him wonder why he hadn’t had any milk in years when it could be this nice to drink.
Bowser thought he could hear one of the visitors saying something and he turned to growl at them. Or at least he tried to. The magic had too firm a grip on him. He was being rocked, he was sucking on milk, and now there was a soft melody at the edges of Bowser’s hearing. One of his favourites, that his parents had always used, and that he used for his own children whenever they had trouble sleeping.
It was almost like Bowser himself was the baby he was being forced to dress as. There was a tension in his body that Bowser had not realised was even there, slowly unwinding. He had to be intimidating all the time. And now that he was forced into this position, now that the magic prevented him from fighting it, maybe it would be okay to let go for just a few moments.
“Oh my god, is he wetting himself?” Left Toad asked.
Bowser’s eyes shot open. He forced through the magic’s restraints and roared so loudly that the castle shook on its foundations.
Finally the magic keeping him aloft dropped away. Bowser landed with a crinkly squish on his bottom and got up immediately.
“Let me go!”
Bowser looked to the sky, where his most mischievous underling was being held up by the scruff of his neck.
~*~
Shade had been having so much fun with his Voodoo doll! The doll clothes looked so much better on the real sized Bowser and it was hilarious seeing the big strong Koopa King dressed like the unfair baby he had been acting as.
It was his surprised yelp at the roar that had given him away, and the Sky Troopa had heard Shade and captured him. He kicked and fussed, but the guard had a good grip. He was holding Shade in one hand, and the Voodoo doll in the other, lowering down to Bowser’s level.
Bowser’s eyes were fixed on the doll, shaped like a Bowser plushie and looking like a miniature version of his current situation. It had the small baby pamper put on and the mittens and booties too.
“That wasn’t funny, Shade.” Bowser growled.
“It’s only fair!” Shade said. “Shouldn’t have been such a meany butt yesterday, and then you wouldn’t have had to be a crinkly butt today!”
Bowser pulled the Voodoo doll away, inspecting it. Proof of everything that had been done, one humiliation after the other. “Yesterday is going to be a visit to the playground compared to what I’m going to do to you for this.”
The guests were laughing, pointing at Shade’s diaper. “It’s going to be hard to keep the two of them apart.”
Bowser snapped at them. “One more word and you’ll learn the definition of pain!”
They looked intimidated, but only until Bowser’s focus was back on Shade. Even Bowser couldn’t sell intimidating bad guy with a few inches of soggy padding around his hips. It did help when he put one of the mittens between his sharp teeth and tore it off with brute strength.
Bowser took Shade from the Sky Troopa and stomped away. His booties were still squeaking which almost made Shade giggle, except Bowser was looking so serious that he didn’t even seem to register the sounds.
“Where are we going?”
“I’m going into a changing room to get this ridiculous outfit off me. And you’re going with me because you’ve proven you can’t be trusted unsupervised.”
Shade sulked. “And then my punishment before or after the super important conference that meant you couldn’t play with me all day?”
“And then, we are going back to that room together and all of the guests can witness your punishment.”
Shade gulped.