Pokemon Tower Jessie & James Battle

Walkthrough
With Team Rocket defeated and the Celadon City Gym conquered, you can return to the Pokemon Tower in Lavender Town to save Mr. Fuji. With the help of the Silph Scope, you will no longer have to fear the Ghost Pokemon in Pokemon Tower as they can't send you packing like before. Once on the Sixth Floor of the Pokemon Tower, you and your Rival will come face to face with the restless Spirit. Now that you have the Silph Scope, the spirit will be revealed as Cubone's mother, Marowak. Just as Cubone goes to embrace its mother, Marowak's spirit will finally be at peace and disappear.

Once it has, you will be able to ascend to the final floor of Pokemon Tower to save Mr. Fuji. Of course, as you do, you will find Jessie and James are the ones holding Mr. Fuji hostage. You will need to defeat them in battle once more to send them blasting off (mentioning the Silph Co as their next destination), and after you do, Mr. Fuji will award you with the Pokeflute. With it, you will be able to awaken sleeping Pokemon blocking certain paths across the Kanto Region.

Team Rocket Jessie & James
Level 34 Arbok: Poison Jab, Glare, Crunch
Level 34 Weezing: Dark Pulse, Sludge Bomb