We discuss the structure of those polytopes in /R/n+ that are Minkowski sums of prisms. A prism is the convex hull of the origin and "n" positive multiples of the unit vectors. We characterize the defining outer surface of such polytopes by describing the shape of all maximal faces. As this shape resembles the view of a cephalopod, the polytope obtained is called a "cephoid". The general geometrical and combinatorial aspects of cephoids are exhibited.