Program.cs

using System;

namespace WeirdDynamic
{
    class Program
    {
        static void Main(string[] args)
        {
            var foo = CreateFoo();

            var bar = CreateBar(foo.Id);

            Console.WriteLine(bar.Id);
        }

        static Bar CreateBar(int id) => new Bar(id);

        static dynamic CreateFoo() => new { Id = 42 };

        class Bar
        {
            public Bar(int id) { }
        }
    }
}