After a look at some strange creatures, the narrator and camera take us to the Chaco forest, on the borders of Paraguay, Argentina, and Brazil, where a vampire bat lives, desmodus rotondus, attacking wildlife and domesticated creatures, killing small ones by draining all their blood and killing large ones by leaving a parasite in their bloodstream. Four inches long, with a 12-inch wingspread, we see it walk, approach a victim, pull out a patch of fur large enough for it to engage its teeth, then lap six or seven ounces of blood. Its saliva may be an anesthetic keeping its victims from waking. A stub nose and harelip contribute to its efficiency and its hideous look.

Uma exploração genial do vampiro como um arquétipo biológico. Animado por uma alegre trilha sonora de Duke Ellington, este filme é uma alegoria alegremente mórbida de Painlevé sobre o nazismo.