Trail

            // trail

            trailRenderer = GameObject.AddComponent<TrailRenderer>();

            // Configure the TrailRenderer's properties

            trailRenderer.time = 20.0f;  // Duration of the trail

            trailRenderer.startWidth = 0.5f;  // Width of the trail at the start

            trailRenderer.endWidth = 0.0f;    // Width of the trail at the end

            // a material to the trail

            trailRenderer.material = new Material(Shader.Find("Sprites/Default"));

            // Set the trail color over time

            Gradient gradient = new Gradient();

            gradient.SetKeys(

                new GradientColorKey[] { new GradientColorKey(Color.white, 0.0f), new GradientColorKey(Color.red, 1.0f) },

                new GradientAlphaKey[] { new GradientAlphaKey(1.0f, 0.0f), new GradientAlphaKey(0.0f, 1.0f) }

            );

            trailRenderer.colorGradient = gradient;