CallWhenTrue.cs

using UnityEngine;

public class CallWhenTrue : MonoBehaviour
{
	System.Func<bool> test;
	System.Action action;

	public static CallWhenTrue Create( System.Func<bool> test, System.Action action)
	{
		CallWhenTrue cwt = new GameObject("CallWhenTrue").AddComponent<CallWhenTrue>();
		cwt.test = test;
		cwt.action = action;
		return cwt;
	}

	void Update()
	{
		if (test())
		{
			action();
			Destroy ( gameObject);
		}
	}
}