Really simple ObjectPool for Unity

ObjectPool.cs

using UnityEngine;
using System.Collections.Generic;

public class ObjectPool : MonoBehaviour {
	private const int MIN_AMOUNT_OF_POOLED_OBJECTS = 5;

	private static ObjectPool _instance;
	public static ObjectPool Instance {
		get{
			if(_instance == null) {
				var go = new GameObject("ObjectPool");
				DontDestroyOnLoad(go);
				_instance = go.AddComponent<ObjectPool>();
			}
			return _instance;
		}
	}

	private Dictionary<GameObject, Stack<GameObject>> pooledObjects = new Dictionary<GameObject, Stack<GameObject>>();

	public void Preload(GameObject go, int amount) {
		if(!pooledObjects.ContainsKey(go)) {
			pooledObjects.Add(go, new Stack<GameObject>());
		}

		for (int i = 0; i < amount; i++) {
			var goInstance = GameObject.Instantiate<GameObject>(go);
			var poolMember = goInstance.AddComponent<PoolMember>();
			poolMember.OriginalGameObject = go;
			goInstance.SetActive(false);
			goInstance.transform.SetParent(this.transform);
			pooledObjects[go].Push(goInstance);
		}
	}

	public GameObject Instantiate(GameObject go) {
		if(pooledObjects.ContainsKey(go) && pooledObjects[go].Count > 0) {
			var pooledGo = pooledObjects[go].Pop();
			pooledGo.transform.SetParent(null);
			pooledGo.SetActive(true);
			return pooledGo;
		}
		else {
			Preload(go, MIN_AMOUNT_OF_POOLED_OBJECTS);
			return Instantiate(go);
		}
	}

	public void Destroy(GameObject go) {
		var poolMember = go.GetComponent<PoolMember>();
		pooledObjects[poolMember.OriginalGameObject].Push(go);
		go.transform.SetParent(this.transform);
		go.SetActive(false);
	}


}

public class PoolMember : MonoBehaviour {
	public GameObject OriginalGameObject {get; set;}
}