Esta es la versión de autor de la comunicación de congreso publicada en: This is an author produced version of a paper published in: A model mutant is a variation of an original model, created by specific model mutation operations. Model mutation has many applications, for instance, in the areas of model transformation testing, model-based testing or education.In this paper, we present a domain-specific language, called Wodel, for the specification and generation of model mutants. Wodel is domain-independent, as it can be used to generate mutants of models conforming to arbitrary metamodels. Its development environment is extensible, permitting the incorporation of post-processors for different applications. As an example, we show an application consisting on the automated generation of exercises for particular domains (automata, class diagrams, electronic circuits, etc.).