>>26585048The stones are the synergy stones from Pokken. The blue ones are regular stones, the yellow ones are dark stones. After filling out some requirement, you can syncro with one of your Pokemon, but only one per battle. They don't change, just glow and shit, and get some bonus, which is different depending on the stone used. If the Pokemon is also holding a Mega Stone, they'll Mega Evolve and get the mega's bonuses on top of that.
