Pokemon SMD: Mewtwo VS The Ninja Duo! (No - Damage/items used)
A strategy using Shedinja and Greninja as a team. Shedinja is completely unaffected by Mewtwo. Snatch prevents Mewtwo from recovering its HP, so I had no need to use a ban seed. There are several other strategies for battling Mewtwo. You can even have your pokemon hold a warp looplet and pretty much troll Mewtwo by waiting till you warp to a spot you can't be attacked and then attack using a move that hits the whole room (Like Blizzard or Surf). During the second phase of the battle - Mewtwo will randomly mega evolve to either its X or Y form. Thankfully it no longer has the ability pressure after mega evolving, so therefore you don't really need a truant wand if your attack pp for moves is high enough. I have another video showing battle with Mewtwo VS Greninja "head on" with no item/held item usage at all. Feel free to leave a comment or tell me of a favorite strategy you like to use.
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