You use unusual gravities to adjust your vital strikes.
Benefit(s): When using any Vital Strike feat in an area of light or heavy gravity, roll the weapon’s damage dice for the attack one additional time. For example, if using Improved Vital Strike, you would roll the weapon’s damage dice for the attack four times before adding other damage bonuses, instead of three times. You must have the appropriate prerequisite feat associated with the plane’s gravity trait to gain this benefit.
Pathfinder Roleplaying Game Planar Adventures © 2018, Paizo Inc.; Authors: Robert Brookes, John Compton, Paris Crenshaw, Eleanor Ferron, Thurston Hillman, James Jacobs, Isabelle Lee, Lyz Liddell, Ron Lundeen, Joe Pasini, Lacy Pellazar, Jessica Price, Mark Seifter, F. Wesley Schneider, Todd Stewart, James L. Sutter, and Linda Zayas-Palmer.