Effect.cs

using UnityEngine;
using System.Collections;

public class Effect : MonoBehaviour
{
    public Gradient gradient;
    float time;
    public float LifeTime;
    public float ScaleModifier;

    void Awake ()
    {
        transform.rotation = transform.rotation * Quaternion.Euler (0,0,Random.Range(0,360));
    }

    void Update ()
    {
        time += Time.deltaTime;
        transform.GetComponent<MeshRenderer> ().material.SetColor ("_TintColor",gradient.Evaluate(time/LifeTime));
        transform.localScale += new Vector3 (ScaleModifier/2, ScaleModifier/2, ScaleModifier);
        if (time / LifeTime > 1)
        {
            Destroy (gameObject);
        }
    }
}