In order to better understand the specificity of mystification, it is necessary to reflect upon an oft-neglected point in poetics : the issue of the convergence between mystification and parody. Maybe because mystification operates on a wilder than parody, in that it is not limited to the literary and cultural domains nor to the misappropriation of a code, the pragmatics it relates to is rather more fragile, and it tends to engage is more flirtation with the undecidable and with nothingness. The theatrical mystification analysed in the article (Cogniard and Clairville’s La Grande Marée, mystification en 2 actes mêlée de chants [1860]) also points out the instability of a mystification-mise-en-abyme which, much more then the numerous theatrical parodies then fashionable, plays at several levels with the boundaries between fiction and reality.