The Middle Ages are often perceived as a period marked by obscurantism and religious rigour that restricted visual representations. Yet medieval art is full of transgressive and provocative images. From the margins of prayer books to church facades, grotesque and irreverent images abound. These representations were not trivial, but often served as moral repellents. This extremely rare 15th-century corbel beam carved in Brittany proves the point. Adorned with a jester indulging in onanism or a man disguised as a squirrel, it echoes a well-known 13th-century bawdy fabliau, the Escureuil. Offering a fascinating insight into medieval literature and society, this mischievous setting raises with a touch of humour questions about the role of images at the time, their rich semantics and their place in space. Illustrating immoral behaviour through comic metaphors, this set plays on satire and humour to offer the audience a critical reflection on social and moral behaviour, providing both laughter and protection.