Rock Smash

You strike out with a rock-crushing attack that may lower a user’s defense. Make an attack roll against a creature, doing 1d6 + MOVE fighting damage on a hit. If the natural attack roll is 19 or 20, the target’s AC decreases by 1 while it remains in battle.

At Higher Levels: The damage dice roll for this move changes to 1d12 at level 5, 2d8 at level 10, and 4d6 at level 17.