I was doing a Max Raid battle and I used Sheer cold on the dynamaxed Pokémon, but it said this move won't work, or something along those lines. I was curious if it was just that battle or if they can't affect dynamaxed pokémon. Thanks in advance!
In Max Raid Battles, one-hit KO moves can deplete two bars of strength from a mysterious barrier, but will otherwise always fail against Dynamax Pokémon.
One-Hit KO moves do not affect dynamax Pokemon, however it does break two bars of the pink barrier.
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