  The ``ugly duckling'' of the Segr\'e-Pleba\'nski-Hawking-Ellis classification
of stress-energy tensors is believed to be either impossible or extremely
difficult to realise in Einstein gravity. Effective stress-energy tensors in
alternative gravity offer a wider range of possibilities. We report a class of
type III realisations in ``first-generation'' scalar-tensor and in Horndeski
gravity, and their physical interpretation. The ugly duckling may be a freak of
nature of limited importance but it is not physically impossible.
