Instant Crater
You can calculate the angle and timing of your explosive weapons to damage the ground, making the terrain treacherous.
Preqrequisite
Base attack bonus +5.
Benefit
As a standard action, you can make a ranged attack using a weapon that has the explode weapon special property, targeting an intersection as normal and choosing one square adjacent to that intersection. If you hit the targeted intersection and your damage roll exceeds the hardness of the material of the chosen square, that square becomes difficult terrain. This is in addition to the normal effects of the weapon.
Source
Character Operations Manual pg. 116
Dragonscript
ID
773d16310e549ad486cca4a9
Preqrequisite
condition character.bab.featPrerequisite >= 5;