Preventing a gameobject from looking upwards?

I have a gameobject that looks at another gameobject above it using Quaternion.Slerp. I want the gameobject on the ground to look in the direction of the other gameobject in the air but I don't want it to look up directly at it. I want the gameobject on the ground to have its rotation.x to be 0 so it doesn't look upward at the gameobject above it. This is the code I have but its still attempting to look up at the gameobject in the air. Quaternion LookRot = Quaternion.LookRotation (controller.chaseTarget.position - controller.transform.position); Quaternion Rot = new Quaternion (0f, controller.transform.rotation.y, controller.transform.rotation.z, controller.transform.rotation.w); controller.transform.rotation = Quaternion.Slerp (Rot, LookRot, Time.deltaTime * 10);