A Grease spell covers a solid surface with a layer of slippery Grease. Any Creature in the area when the spell is cast must make a successful Reflex save or fall. A Creature can walk within or through the area of Grease at half normal speed with a DC 10 Acrobatics check. Failure means it can't move that round (and must then make a Reflex save or fall), while failure by 5 or more means it falls (see the Acrobatics skill for details). Creatures that do not move on their turn do not need to make this check and are not considered Flat-Footed.

The spell can also be used to create a greasy coating on an item. Material objects not in use are always affected by this spell, while an object wielded or employed by a Creature requires its bearer to make a Reflex Saving Throw to avoid the effect. If the initial Saving Throw fails, the Creature immediately drops the item. A Saving Throw must be made in each round that the Creature attempts to pick up or use the greased item. A Creature wearing greased armor or Clothing gains a +10 circumstance bonus on Escape Artist checks and Combat Maneuver checks made to escape a Grapple, and to their CMD to avoid being grappled.