Instructions
Travel to an area where Wobbuffet is found. Wobbuffet can be encountered in the basement and on the first and second floors of Cerulean Cave. Wobbuffet is also found in Ruin Valley.
Battle Wobbuffet using your strongest Pokemon to cut down its health points. You want to weaken Wobbuffet but not completely defeat it or you will have to wait until you encounter another Wobbuffet to try again.
Throw a Pokeball when you have significantly weakened the Wobbuffet to capture it. If the Wobbuffet will not stay in the Pokeball, weaken it further and try again.
Add Wobbuffet to your party and put it in the first slot in your Pokemon roster. This will make Wobbuffet the first Pokemon you use in each battle. Shadow Tag is an automatic ability, so as long as Wobbuffet is your starting Pokemon, you will never have a wild or Legendary Pokemon run away at the start of a battle.