The repertoire of cult-iconography produced in Gaul and Britain during the Iron Age and Roman periods contains a group of images that are a blend of human and animal forms. Such pieces are generally interpreted as depictions of divinities, but while it remains probable that they are expressive of cult perceptions, there is a need to re-evaluate their function and identity. The hybridity of the images suggests meanings associated with boundary-crossing, risk and the challenge to ‘normative’ concepts. It is argued here that such contradictive and liminal representations might be identified with transgression between earthworld and spiritworld, and that monstrous images perhaps express the identity of individuals who, within the context of ritual practice, habitually ‘moved’ between worlds, by means of trance and altered states of consciousness. It may be that, in the context of Gallo-British cosmologies, images with antler-head-dresses, horns or other animal attributes should be identified as shamans rather than as gods.