After choosing your starter Pokemon; Squirtle, Charmander, or Bulbasaur, from Professor Oak. You then proceed on into the wild where you encounter wild Pokemon. Route 1 is the first area in the game you will encounter Pokemon, which are just Pidgey and Rattatas in the original Red and Blue games.
From there you will find yourself in Viridian City, which will eventually get you to route 2. Route 2 is the home of Caterpie, Weedle, Pidgey, and Rattata until you get to Viridian’s forest; you can add Metapod, Kakuna, and Pikachu to the list. These are the Pokemon that again, show up in the Red and Blue games.
After doing a short tutorial on how to catch Pokemon in Pewter City, and a quick exploration of the town, trying to get into the gym you forgot was owned by the 8th gym leader; route 3 is just east of the city.
Home to Pidgey, Spearow, and Jigglypuff, some may already see where I’m going with this. The only Pokemon we are missing so far would be Geodude, Zubat, and Clefairy.
After completing route 3; defeating all the trainers and making it to the other side so you can heal your Pokemon, you will find yourself standing with what appears to be, nowhere to go. Don’t worry, though, that little black dot is to a cave, Mt. Moon.
Those missing few Pokemon can all be found here, plus Paras. I’m not sure why Niantic didn’t include Paras in the same egg group, or maybe what I came across is just a mere coincidence, but I don’t believe so. The odds of the developers making all these wild Pokemon in the Red and Blue games; found before and in Mt. Moon, being nothing more than luck just doesn’t cut it for me.
There is a reason I believe this to be an easter egg, only involving the Pokemon Red and Blue games. I did quite a bit of research. At first I suspected it might have been the first Pokemon Ash registered in his Pokedex. A few episodes in I noticed Ash registered a bug trainers Pinser in his Pokedex, so I went on to believe that maybe it was only wild Pokemon. 10 Pokemon into the theory, Ash Catches a Krabby, busting the theory and putting my semi-hard work to shame.
I don’t remember why I decided to research all the Pokemon that spawn in the games, Red, Blue, and Yellow, but I did. I started getting a little disappointed when I saw that Sandshrew could be caught in Mt. Moon. At the time I was just skimming the bulbapedia articles, only later to catch on that I found what I was looking for. Until Niantic confirms this, which I doubt they will see it, I’m still not 100% sure this was intended.
If it wasn’t for that one extra Pokemon, Paras. I would feel more comfortable about saying this is, in fact, an easter egg. Aside from Paras though, all the Pokemon caught up until this point are the same Pokemon we can hatch from 2km eggs. My biggest question about the 2km eggs was, why do we hatch, out of all the other Pokemon, Geodude from 2km eggs? I told myself I wouldn’t stop until I found an answer and I did! The thing about Magikarp being hatching from 2km eggs is because of the amount of candies it takes to evolve.