duck

var degrees : float;
var offset : Vector2 = Vector2(0.5, 0.5);

function Update() {
    degrees = Input.mousePosition.x;
    rotation = Quaternion.Euler(Vector3(0,0,degrees));
    trans = Matrix4x4.TRS(-offset, Quaternion.identity, Vector3.one);
    rot = Matrix4x4.TRS(Vector3.zero, rotation, Vector3.one);
    inv = Matrix4x4.TRS(offset, Quaternion.identity, Vector3.one);
    renderer.materials[1].SetMatrix("_Rotation", inv*rot*trans);
}