C# Tiny Generic Array Class

TinyArray.cs

[Serializable]
    public class TinyArray<T>
    {
        public int Count;
        public T[] Thing;

        public TinyArray() : this(4096)
        {
        }

        public TinyArray(int cap)
        {
            Count = 0;
            Thing = new T[cap];
        }

        public T this[int index]
        {
            get
            {
                if (index > Count)
                    throw new Exception("Error: Index out of range.");
                return Thing[index];
            }
            set
            {
                EnsureSize();
                Thing[index] = value;
                Count++;
            }
        }
        private void EnsureSize()
        {
            if (Count + 1 > Thing.Length)
            {
                var NewLength = Thing.Length == 0 ? 4096 : Thing.Length * 2;
                var newtArray = new T[NewLength];
                Array.Copy(Thing, 0, newtArray, 0, Count);
                Thing = newtArray;
            }
        }
        public void Add(T item)
        {
            EnsureSize();
            Thing[Count] = item;
            Count++;
        }

        public T[] ToArray()
        {
            var newtArray = new T[Count];
            Array.Copy(Thing, 0, newtArray, 0, Count);
            return newtArray;
        }

        public void Clean()
        {
            var newtArray = new T[Count];
            Array.Copy(Thing, 0, newtArray, 0, Count);
            Thing = newtArray;
        }
    }