So, normal form is the annoying one, with protean and moves of all different types. Nuke this one down. Then defense mode's stamina is going to power up its body press, use special attackers for this. Sac a mon/protect for atk mode, and spd only has tackle but it can still deal damage to any glass canons. Shouldn't be too hard, but be mindful that it (at least for me) always hangs on with a sliver of hp like a focus band.