>>35200071It won't be STAB. Primarina is the slower one, and Water + Grass pledge always results in the second user firing off a 150 BP Grass move using the faster mon's speed stat.
>>35200319This one probably is better for damage, while the one on the OP is coverage. Frog uses Mat Block and Owl uses Nasty Plot turn 1. Then they use their combined pledge moves, Owl uses a fast Grass type hyper beam off of +2, and for the next four turns the opponent is slow enough for Decidueye to actually have a speed advantage for once.