...I have no idea what I was smoking when I decided to write this. This is the Netherlands, so I guess it could've been anything. Anyway. I was looking at TV Tropes' page Mister Seahorse, and they added an illustration with merman!Sora and pregnant!seahorse!Riku. Me being me, obviously I had to add this to my plotbunny orphanage. Guess it found a home after all.
This fic was written partially as a Take That to people who write Mpreg seriously (by presenting them with the only way this would ever work), partially because the fanart was just that inspiring, 100% Because I Felt Like It.
Fair Warnings: yaoi, mpreg, Atlantica biology-fail. Rating for mpreg and (not shown) gay sex, otherwise innocent.
Disclaimer: I don't own Kingdom Hearts. Square Enix and Disney do.
Anyways. Enjoy!

"You are dead!"
"But- but Riku, I-"
"Start digging your grave!"
"It was just an-"
"Dead and buried!"
"I didn't know this was going to happen, either!" Sora cried.
"Save the excuses for someone who cares! 'I didn't know' is not a valid excuse for... for... this!" I shouted, gesturing towards my stomach. "You did this to me!"
"How was I supposed to know you'd end up pregnant?"
I shuddered. Goddamn it, he was using the p-word. "I was trying not to use that word," I hissed. "And how the hell am I going to give birth –" another shudder "– looking like this?" I moved my new seahorse-tail, silently cursing the day Sora suggested going to Atlantica. I'm okay with him visiting this place every now and then, but why, oh why, did he have to drag me into this place?
"I'm sure Yen Sid can think of something if you just go back right now..." Sora said uncertainly.
Oh. Right. Yen Sid. "Why should I, though?..." I muttered under my breath. It's not like Yen Sid wasn't powerful and wise and stuff. It's just that figuring out Atlantica's laws of nature was several times more important than the life of one of the Keybearers.
And besides, it's not like he sounded like he knew anything, either.
"I'm afraid this is the first case of this nature I've heard of. It would be unwise to haste this since we do not know how the pregnancy will affect you. This is truly unique." Wizard-to-human translation: You're fucked. I have no idea what the hell I'm supposed to do because this never happened before, you speshul little snowflake, you.
Sid couldn't remove the little whatever either, since "I don't know how the fetus is attached to your body. Removing it might do more harm than good. All I can do is give you prenatal vitamins and monitor your pregnancy closely." Wizard-to-human translation: I know squat about knocked up seahorse-mermen, so get some vitamins and keep your fingers crossed.
...stupid Sora and his stupid hormones. If it weren't for him, I wouldn't be in this mess.
I sighed. "Fine. I'll go see if Yen Sid figured something out. But I swear to God that unless he treats me as a person instead of a lab rat, I'm going to strangle someone."
I pretended not to hear the little voice in the back of my head telling me I was already acting the part of stereotypical hormonal mom-to-be. I can only take this much crap before I lose my sanity, thank you very much indeed. The next few months would be interesting... Oh boy...

...I'd like to apologise to everyone, everywhere for writing this.
Sporkers are free to snatch and spork, just as long as I know where, okay?
Anyways, review, please!