duck

using UnityEngine;
using System.Collections;

public class LifeTime : MonoBehaviour {

    private Color colorStart;
    private Color colorEnd;
    private float duration = 1.0f;
        private float startTime;

    void Awake() {
        colorStart = renderer.material.color;
        colorEnd = colorStart;
        colorEnd.a = 0;
                startTime = Time.time;
    }

    void Update () {
        float lerp = Mathf.PingPong (Time.time - startTime, duration) / duration;
        gameObject.renderer.material.color = Color.Lerp(colorStart, colorEnd, lerp);
    }

}