gistfile1.cs

    class Program
    {
        static void Main(string[] args)
        {
            var foo = (MyType<string>) "cat";
        }
    }

    public class MyType<t>
    {
        private t _value;

        private MyType(t val)
        {
            _value = val;
        }

        public static implicit operator MyType<t>(t obj)
        {
            throw new Exception("WOOPS!");
        }
    }