[This one gets into some pretty weird stuff. And it is 100% my fault. Please forgive me.]
[This also won't be entirely logical. But, then again, trying to mix logic and fiction is like trying to mix Helium and Neon.]
[This was mainly done on impulse. You know..."impulse". An...erm...yeah. I've been busy visiting family and actually enjoying my days off, so I haven't had time to...y'know...do the thing that you're on this website for.]
[This is written from the PoV of Mewtwo]
[Also, we're just gonna dive right into the action. Mainly because my friend is, again, playing Counter Salt: Globally Offended.]
[This final bracket is to let you know that all brackets from this point on will only serve to remind you of how far I have fallen in terms of sanity.]

Charizard and I had been walking for miles, in need of a place to sleep for the night. We eventually found ourselves in a rundown city that looked like it had been abandoned for some time. It had people living in it, mind you. It just looked like the type of ghetto that would be the breeding ground for some new disease or crazy drug. In other words, not an ideal place to spend the night, but Charizard and I were more or less out of options. We didn't have enough supplies to make it to the next town, not to mention my need for a bathroom that wasn't a tree or bush. So staying in the demilitarized area was our only option. Thankfully, there was a functional Pokecenter. Or...somewhat. It had been rundown, just not nearly as much as...basically the rest of the town. Charizard and I walked in, and he asked if we could stay for the night. The head nurse politely agreed, and Charizard almost immediately went and crashed on the couch. I turned to her and asked her if they had a functioning bathroom, and she pointed to the far left corner of the room. I thanked her, and aggresively floated [MY FAVORITE LINE IN THIS ENTIRE THING] towards the door. I opened it, the sound of a loud creak echoed throughout the graffiti-ridden bathroom.
Walking in, the first thing I noticed was the smell. It smelled like it hadn't been cleaned in weeks, or maybe months. Atleast half of the 6 urinals were out of order, and one of the stall doors for the toilets was broken clean off. "Okay, Mewtwo." I said to myself. "It's a little more rundown than you originally thought. But, that's OK. It can't get any worse than this. After all, you're only gonna need to do this once." I have had issues..."going" under pressure, or infront of people for as long as I can remember. I scanned the 3 functioning urinals, and chose the one that was the least unsanitary. Despite having held it in for the entirety of the trek, I stood there for a good 5 minutes trying to focus on getting it over with, which is a lot harder than it sounds. Eventually, I managed to coax my urine out, which quietly streamed into the slightly yellow-stained bowl infront of me. Not long after that, I heard the bathroom door squeak open. I turned to see a particularly arrogant Blastoise, walking with narcissistic strides, and a blue bandana wrapped around his head. Trailing behind him was a slightly, and I mean slightly, less noticable Lucario, this time with a gray bandana. And behind him, surprisingly, a black Charizard, with a blue fire spirting out from where the two halves of his strangely rectangular jaw met. Oh sweet Arceus, what did I do to deserve this? I thought to myself, trying not to seem embarrased in front of the three """"""gangsters"""""" who just walked in, and had started staring at me like I was an alien from Mars.  
"Jesus f#&%, do I gotta p@%$!" the Blastoise said, walking past me.  "Well, we can't do what we'd normally do, the new guy would probably snitch us out!" the Lucario retorded. "Did I ask for your input, Lucy? No, I don't remember asking for it at all!" As he finished this statement, he turned and looked me dead in the eyes. The Charizard took the stall with an actual door. As the door slammed shut, the Blastoise scoffed at me, not even knowing what I could do. "You really think this guy can cause us problems? Ha! He couldn't hit the broad side of a barn with a f#&$ing RPG!" I ignored this at first, mainly because I more or less expected it from this town. "Here, i'll prove it!" He walked towards the back of the bathroom, reached down towards his crotch, and sighed in a forced-pleasure kinda way, as he began to coat the wall with his urine.
I froze in awe. You have GOT to be kidding me right now! Wh-...what does he expect me to do about that? I tried to think a way to punish him, but then my mind struck gold. For the time being, I just focused on what I was doing. The Blastoise, now standing in a sizable puddle of his yellow rebelliousness, stated: "You see Lucy? Nothing! He doesn't care what we do. Now quit your b#&$%ing and p&#@ on the wall!" The Lucario, reluctantly, joined. The only sound in the room was the Blastoise and Lucario hosing down the wall. The Charizard occasionally punctuating this sound by clearing his throat from inside the stall. After what felt like an eternity of listening to those two...do what they were doing, I put my plan into action. Almost as soon as they finished, and they turned around to leave, I shut the bathroom door and held it shut. 
The Blastoise turned around, saying "Oh-ho! We got ourselves a bad#&$ don't we!" I shut him up immediately. "Now, you listen to me" I said, still in the midst of wrapping up the reason I went in there, "You make the mess, you can clean it up. I don't care how, but all of the mess you made WILL be cleaned up before you're allowed to leave. Do you understand me?" The two Pokemon nodded, and the Charizard burst out laughing. I went and leaned against the door, which was opposite of the urine pool that Blastoise and Lucario had made. Not a minute later, Blastoise looked at me and asked sarcastically, "And just how do you expect us to clean this mess up? There's no toilet paper, paper towels, or anything to mop it up with!" I looked at him, and repeated my previous statement with a bit more emphasis, "I already told you, I don't care how. I could give you a suggestion, but you wouldn't like it." They both looked at each other scared. The Lucario swallowed hard, before asking, "W-What is your idea?" I responded, in possibly the most roundabout manner, "Well, you could always recycle." The Charizard fell off the toilet, laughing so hard he sounded like he was having an asthma attack (he wasn't, I checked). The Blastoise, somewhat P.O'd, asked "What the f#&$ do you mean, 'recycle'? You want us to drink this s#&$?" I said sarcastically, "No, you don't drink a solid. You drink a liquid, and you have a mess to clean up. Put it together, Einstein."
"You've gotta be f#&%ing me." said the Blastoise, unable to come up with a decent response. "That can be arranged, if that's really what you want. I have a friend who would be all over that idea." At that point, they both shut up and got to work. The bathroom was almost immediately filled with the sound of the two embarassed Pokemon lapping up their mess. About 5 minutes in, the Blastoise started gagging with every swallow. I snapped my fingers at him, then said, "If you throw up, you have to down that too." I'm still not sure if that helped, but thankfully it didn't come to that. After that, I held up my end of the bargain and let them free. The Charizard came out, saying "I knew one day somebody would put them in their place, I didn't expect it to be that funny though!"
And that's why I hate..."going" in public bathrooms.