remove snorlax

Speedrunners now have a technique to make Snorlax vanish from both east of Route 11 and west of Celadon City without obtaining the pokéflute. If you are not speedrunning you would probably prefer to get the flute anyway so you can catch both Snorlaxes, but you can try out this glitch just for show's sake.

In the description of his tool-assisted speedrun, primorial#soup wrote an excellent overview of this glitch and its history:

Snazzypadgett from the SDA (Speed Demos Archive) forums noticed that after performing the Trainer-Fly glitch, that he (or rather, a friend of his) had managed to make Snorlax disappear. Details were vague, but after experimentation, several people were able to reproduce this. Hanzou did a lot of research on this glitch, and found that it was not only Snorlax, but the last disappearable object seen before or during the glitch, where a disappearable object can be a number of things: Snorlax, Legendary Pokémon, item balls, guards, and even Rival battles.

The set of objects that can actually be removed with this glitch is actually quite limited. The two Snorlaxes are the only such disappearable objects that provide real shortcuts. Below is a step-by-step procedure. It requires that you understand the Mew glitch, so go back and read that section if you haven't already.

Visit Snorlax.
Perform the Trainer-Fly glitch (a.k.a. the "Mew" glitch, although you are free to catch any pokémon other than Mew), and complete it in the areas surrounding Vermillion City. You can use trainers in other locations, but make sure you do not pass through Cerulean City, Saffron City, or Pewter City.
You'll generate some level 7 pokémon. You can catch it, or just run away if you like.
When you return, Snorlax will be gone.