A/N I'm going to say this first, the alternate colouring is possible as in Anime colours other than standard have often been shown and the move is possible though events-I know it's not the best source but still kind of, Mew is event only in gen 1 after all-so it's all possible in the Pokémon world just not likely.
Pokémon-Pokémon-Pokémon
Ash had arrived to Professor Oak's place late, arriving just in time to be mocked by Gary-who was leaving last, so clearly was at least a little late himself. Professor Oak had allowed him to enter the lab anyway, and now he was doing it. He was selecting his first Pokémon, the Pokémon that would-in all likelihood-be his partner for his entire journey.
Ash was now looking at his three choices for a Pokémon. He had already made his decision, he was going for Squirtle, the water type, and so with that in mind he reached across and opened it. But nothing came out, when he checked he quickly found that it was in fact empty. "That Pokémon was already taken by someone that was on time" Professor Oak explained simply, still standing completely still with his arms crossed behind his back.
He then reached for his second choice, Bulbasaur the grass type. He pressed the button expecting to see a brand new Pokémon but, once again, nothing appeared. He turned to look at Professor Oak again. "That Pokémon was taken by someone who wasn't late." He stated dryly before continuing to stand still doing absolutely nothing.
Finally he reached for Charmander, it wasn't his first or even second choice, but it was still close so he didn't really mind. He opened and, nothing happened. He glared at Oak who had a philosophical look on his face. "The early bird gets the worm, or in the case the Pokémon"
"Why did you have me open them all just to find nothing?" Ash yelled before he could stop himself. It was just so frustrating, having Professor Oak crushing his dreams by having him to go through all the Pokémon he couldn't have was not pleasant. Fortunately the professor wasn't offended; in fact he didn't even seem to notice.
"Yes I can see how that was a little misleading wasn't it, ha-ha-ha" he laughed to himself making Ash even more annoyed; the professor was clearly enjoying this.
"So do you have any other Pokémon?" Ash asked hopefully no longer caring what he got, as long as it was healthy and a Pokémon it would be good enough.
"Well there is one left but I-"
"I'll take it" Ash yelled not caring about what the problem was.
"Very well" he said activating the mechanism that pushed a poke ball with a small water drop sticker on it up from within the work station. He grabbed the ball and held it "I think I should warn you, this may not be your ideal Pokémon"
"I don't care I'll take anything" Ash said knowing that now was not the time to be picky.
"Well in that case" he shot the Pokémon beam at a small bowl of water and out appeared Ash's Pokémon. It was dark black colour, so black it was like it was sucking in the light from around it. On any other Pokémon this would be cool, but not on this Pokémon.
"Magikarp Magi-Karp" it said splashing in the water just a little, not enough to cause any problems though.
"Its name is Magikarp, you may have heard of it. It is commonly known as the weakest of all Pokémon" Professor Oak introduced it making it even less impressive.
"I-is it supposed to be black, I thought it would be red" Ash said observing the strange fish in its small container.
"No that one of the strange things about this Magikarp" the old man said lightly petting the creature, it responded by happily closing its eyes moving towards him. "It's also part of the reason I need someone to raise it. You see I want to see what happens when it evolves in terms of its colouring, but despite my best efforts I haven't been able to get it to evolve in all the time I've had it. I'm hoping that your training will be able to change that"
"Well…what moves does it know" he asked hoping it being black meant it had super powerful moves.
"It knows splash, which as you know does nothing, flail and tackle. Flail is stronger when the Pokémon is hurt, so don't use it early in a battle" he explained still playing with the happy fish.
"What happened to the other starter Pokémon, shouldn't they have sent one for each of the trainers?" he asked joining Oak in petting the Magikarp, its scales were hard and slimy to the touch; he had to actively fight to continue petting the Pokémon. It was clearly enjoying the attention though, so that helped him get through it. If nothing else Magikarp was clearly friendly, so that was something.
"Yes. Ash there was a break-in, we don't know who or how, but someone managed to steal one of the starter Pokémon that would have otherwise gone to you." He paused to regain control of his anger before he said something he shouldn't say in front of someone so young "But don't worry I've already contacted the police, and their more than capable of solving a crime like this" he lied knowing that the police were not capable from his experience.
"Now take these, your Pokédex and poke balls" he said putting them into Ash's free hand.
"Thank you" and with that Ash returned his new Pokémon to its ball and left quickly, hoping to slip away before anyone saw him.
A plan which fell apart immediately when he saw just about everyone he knew waiting outside with banners to congratulate him on beginning his journey. "Mom" he said trying not to sound embarrassed at the Pokémon he had, hoping that not mentioning it would make it not come up somehow.
"Oh Ash I'm so proud, your finally have a Pokémon partner who will go with you on all your journeys. Where is your Pokémon anyway?" was the very first things she asked, he felt like he should have seen this coming, nothing else had gone well today so why would this?
"It's a water type, so it can't come out its poke ball right now" he tried hoping that would be sufficient, of course it wasn't.
"I thought Squirtle could come out on land" she asked tilting her head in confusion.
"It's not Squirtle…in fact it's probably a Pokémon you've never seen before, Professor Oak said it's very rare. In fact he gave it to me specifically because he needed to have it evolve and knew a strong trainer would be needed to get it done" he was laying it on pretty thick admittedly, but when he saw Professor Oak nodding he knew he would get away with it.
After that it was just an embarrassing talk with his mother to get though… or not. "Hey I have a pond we could all look at it there" a family friend pitched in making Ash feel like crying from shame. He could just imagine what they would say when they saw that his 'special' Pokémon was a Magikarp.
He knew that he should just be happy to have any Pokémon at all, and he was happy. It's just that after saying that it's something super rare and cool he didn't feel like showing them that it was actually something super common that can barley battle.
"Sorry but that can't be done, Ash has to begin raising this Pokémon right away. It's very important for my research" Professor Oak saved him literally pushing him towards route one and the start of his journey. Ash didn't mind though, he had been waiting a long time to begin his journey so he wasn't in the mood to wait around.
Pokémon-Pokémon-Pokémon
After walking a short amount of time Ash arrived at a river and sent out Magikarp. "Ok, now to catch some Pokémon" he said expecting Magikarp to respond in some way, he turned around when it didn't to see it hadn't moved at all.
"So… I was thinking that maybe since it's our first time together we should start with…" he tried to think of a Pokémon that Magikarp would do well against, unfortunately the only one that came to mind was another Magikarp. He knew that capturing more that one Pokémon of the same type wasn't exactly wrong…it's just being known for having an army of Magikarp wasn't all that appealing.
"Ah" a large brown bird Pokémon with sharp claws and a long beak cried as it dived into the water catching Magikarp with its claws. Not being able to think of anything else Ash did took the only option available to him. He jumped, catching Magikarp, and then falling into the water.
Where there had been originally was calm and easy to swim in, so he wasn't too worried when he went so deep underwater. He had to struggle a bit to get back up due to air problems, but he got up quickly.
At least he thought he got up quickly, in realist it became quite clear he didn't when he got up. He looked around and could see nothing, in addition to this he also noticed that the previously gentle flow was now rough and powerful, and was about to push him over a waterfall.
He fell with a mighty crash, holding onto Magikarp tightly as he got pushed though the water. Whenever he would be pushed to the surface he would gasp for air frantically before being pushed back under.
It was horrible, water rushed up his nose making him splutter and cough every time he surfaced and he barely got to take a breath before the current took him back under. Pretty soon he started feeling a little lightheaded, he realised he had no real idea how long he had been in the water for but it didn't feel like long. It was still exhausting though.
Finally he was stopped by something catching onto his shirt.
His shirt was then roughly pulled; surprisingly he was then lifted and thrown roughly onto the water. "Nah it's just a kid" he heard as he coughed up all the water. "Oh and a Magikarp, oh are you ok?" she cooed jumping towards the duo.
"Yeah, I think we're ok" he answered smiling to his rescuer.
"Not you!" she yelled angrily taking the Magikarp from him and putting it in the water "Its injured, why would you grab it" she yelled at him as he came to check on it.
"It's my Pokémon, I was trying to save it from a Fearow when we got stuck in the water" he explained frantically waving his hands around before stopping due to the pain in his muscles.
"Well don't just sit there, there's a medical centre not too far away. Return him to his ball and get there right away" she ordered pointing in its general direction. "Ah-ha" the Fearow's cry was loud as it swooped in from behind them, several Spearow in tow.
Doing as he was told he quickly returned Magikarp to its ball, running and jumping on a nearby bike-probably the loud girls bike-and riding away, ignoring her protests completely as he peddled as fast as he could.
Angry storm clouds formed over head as he peddled, the harsh winds smashing into him with blisteringly cold rain as he continued to peddle. From inside its poke ball Magikarp was able to see this as the water began collecting in the basket he was currently in. It also heard the Fearow as it once again let out a cry before crashing into Ash sending him flying to the ground the Spearow swarming around them.
Magikarp continued to watch as Ash picked up the bike and used it as a weapon to fend of the large bird and successfully made the smaller ones flee. But it was to no avail as the Fearow soon took the bike in its beak and crushed it. "Crap!" he yelled as a hard peck cut his chest sending him to the ground.
Blood started spreading from the wound, it wasn't very deep but it was enough to hurt badly. The blood was spread further when it mixed with the rain and the mud making it seem like there was a lot more then there really was.
"Magikarp!" Magikarp cried releasing itself from its ball and blocking the path between the two. "Magikarp you have to return to your ball, you won't be able to fend of Fearow by yourself" Ash yelled as he shot the red beam at the fish, but it jumped out of the way hitting Fearow with its best tackle.
"Magikarp I'm not kidding this is too dangerous" he yelled shooting the beam several more time as Magikarp continued to try to fight the Fearow. Crash the Fearow's mighty beak finally connected sending the fish back and into Ash's arms, he quickly rolled over so as to shield it from the monster.
He searched for its ball finding it had been knocked away by the last attack. Thunder and lightning went off around them, the sound in perfect time with Fearow's pecks to Ash's back. "It's ok Magikarp, your my Pokémon and I'm going to protect you" Ash ground out though the pain holing Magikarp close.
Blood was now dripping down his sides, Fearow's attacks having formed several cuts that were bleeding painfully. But Fearow clearly wasn't going to stop; he would keep going not caring whether or not Ash was injured.
"Magi-Ka-a-karp!"Magikarp yelled as a yellow ball formed in its mouth, the energy soon flying into the Fearow. Crash the attack collided mightily, the explosion kicking up rubble all around the winged beast obscuring it from Ash's awe struck view.
That moment seemed to last forever, the dust slowly parting to the side. Ash was unable to see Fearow the whole time and felt nothing but fear, if the attack failed then this would definitely be bad. But he would protect Magikarp no matter what.
Finally when the dust had cleared it was revealed, lying there defeated was Fearow. No longer was it a crazed beast instead it laid before them as nothing more than a defeated Pokémon. "Wow Magikarp…what did you just do?" Ash asked still trying to process what exactly had just happened.
"Magikarp"he looked over at Magikarp finding him to still be in one piece, he decided that the exact details could wait. What mattered was that Magikarp was ok "You should rest" he said returning the black fish to its ball noticing how the sky completely clearly in such a short time, it was weird to say the least.
It was then that he saw a strange bird flying into a newly formed rainbow, a strange glitter flowing from behind it. It was an avian Pokémon resembling a phoenix and a peacock. Its feathers were predominantly gold and red, with yellow tail-feathers, a white underside, and green feathers at the tip of its wings. He noticed it also has a green stripe on its neck, a yellow beak, black rings around its red eyes, and a feathered, yellow crest on its head. Finally he noticed it's darkly coloured feet and legs with four toes and long talons. "What's that?" he asked his Pokédex.
"There is currently no data on this Pokémon, it has yet to be identified" it explained unhelpfully. But it did make Ash wonder, a Pokémon that hadn't been identified was interesting. He had always just assumed that all Pokémon had been discovered, but if one hadn't than that meant that it was likely many more hadn't either.
He knew that he would be the one that discovered them, and he couldn't wait to do it with Magikarp at his side.
"Oh yeah I almost forgot" he reached for a poke ball turning and throwing it at Fearow "Poke ball go!" it hit the downed creature, bouncing off it and engulfing it in red light before closing with no resistance. It didn't even shake, Fearow was completely defeated so could put up so resistance at all.
After that Ash collected his two poke balls and continued towards the town knowing that he now had two Pokémon that needed treatment.