Current behavior: Mock.Arrange(xxx).IgnoreInstance(); //mock all future instances of the type on which I set an expectation. Feature Request: Mock.Arrange(xxx).IgnoreInstance().Next(); //mock the next instance of the type on which I set an expectation. ...and even better... Mock.Arrange(xxx).IgnoreInstance().Skip(3).Next(); //mock the 4th instance of a type on which I set an expectation.