transmutation 

Traditions arcane, primal

Cast [>>] somatic, verbal

Range 120 feet; Targets 1 flying creature

Saving Throw Fortitude; Duration varies

Using the weight of earth, you hamper a target's flight, with effects based on its Fortitude save. If the creature reaches the ground safely, it doesn't take falling damage.

Critical Success The target is unaffected.Success The target falls safely up to 120 feet.Failure The target falls safely up to 120 feet. If it hits the ground, it can't Fly, levitate, or otherwise leave the ground for 1 round.Critical Failure The target falls safely up to 120 feet. If it hits the ground, it can't Fly, levitate, or otherwise leave the ground for 1 minute.

Core Rulebook, page 334.