Résumé
Shadows are well known as a programming language feature in the application area of MUDs (a certain type of multi-player online game). We argue that agile methodologies can be enhanced by the use of shadows as this feature because of its inherent ability to dynamically change the behavior of classes and objects, provides mechanisms to ease common tasks such as prototyping, deprecating, dynamic classification and interclassing at run-time. Therefore shadows should be considered a notion beyond any specific programming languages in order to facilitate its use in model-driven software engineering. For this we introduce Shadows-UML, an UML extension, that would help to push forward the convergence between model-driven and agile methodologies.