uncommon conjuration druid plant 

Cast [>>] somatic, verbal

Area ground within a 100-foot emanation

Duration sustained up to 1 minute

The ground within the area transforms into a mass of dangerous briars that assault and impede your foes. The first time you Sustain this Spell each round, you can select one of the following effects to occur in the area.

• Ensnare The briars clump around your foes, attempting to hold them in place. A foe within the area (or flying at most 20 feet above the area) must attempt a Reflex save. On a failure, it takes a –10-foot circumstance penalty to all Speeds for 1 round, and on a critical failure, it is immobilized for 1 round unless it Escapes.
• Impede The briars twist and writhe, making the entire area difficult terrain.
• Wall A wall of thorns appears in the area, lasting for 1 round. The wall is greater difficult terrain instead of difficult terrain

In addition, once per round you can direct the briars to impale any target in the area (or flying up to 20 feet above the area) that you can see by using a single action, which has the concentrate and manipulate traits. Make a spell attack roll. On a success, the target takes 10d6 piercing damage and takes a –10-foot circumstance penalty to all Speeds for 1 round; on a critical success, the target is immobilized for 1 round unless it Escapes.

Core Rulebook, page 400.