Okay, then this is easy...
Walk past Nugget Bridge and left at the end of it. See that grassy bridge right there? Well, go in there, but DO NOT VERSUS THE TRAINER. Now, walk around in the grass until you find an Abra. Catch it when you see it, a simple PokeBall without dealing damage should do the trick. SAVE THE GAME. Now, if the Abra was sent to the PC, store 2 of your Pokemon and withdraw Abra. Why deposite 2 Pokemon? Because you need an extra space in your party to staore Mew. With Abra and 4 other Pokemon in your party, Save the game again, if you want. Head up Nugget Bridge, then swing to the right. You will see a Trainer facing the right, he's one of the first Trainers that will enter your screen. Well, you're gonna have to battle him. After doing so, walk into Cerulean City again, then walk back out onto Nugget bridge and head a left where the Trainer in the grass is (I'll explain later why you need to do this). What you'll want to do now is position yourself to be directly above the Trainer, but have him still be one step-square below the screen's view. To give you a feeling of what I mean, position yourself on the left side on the grassy bridge, just down far enough so that you can see 4 grass squares in a square formation below you. Got that? Now SAVE. When you're ready, step down one square and press Start really fast. If done correctly, your manu should pop up, and the Trainer should be to the left of the menu. Now go to your Abra and tell it to Teleport to the Cerulean Pokemon Center. Once you arrive, your A, B, and Start button will not function.
Now, you can battle one of two Trainers now.
You can either battle the first Trainer in Misty's Gym (This way is easier) or you can battle the Trainer on the Route to the right of Nugget Bridge with the Slowpoke. Let's go with the Gym Trainer now, though.
When you walk into the Gym, walk in front of the swimming Trainer and defeat him. Now walk out side of the Gym. Save the game, buy PokeBalls, heal your Pokemon, whatever you need. When you're ready, walk up Nugget Bridge. While walking, your menu should suddenly pop up. Simply press B, and... MEW!
Owner of the formerly ranked number one Halo PC modded server in the world, FRIGID MASS CTF WAR. Joiner-friendly mods and five-minute hotfixes = loyal clientele.
Been here since February 2004. It's May 2022 as of writing this. Wish Rich would revive this place. Guess I'm only here for the nostalgia now.