Baudelaire's bestiary is well known for its large birds loaded with symbols (thinking owls, lost swans, or splenetic albatrosses), his good dogs or wriggling doggies, and especially his cats, all imbued with a mysterious and fascinating felinity. What is less known, however, is the small creeping fauna that seems to have taken up residence in Baudelaire's poems, to infest them and vivify them at the same time. Worms, vermin, wormlings, but also flies, bugs, spiders, ants, pupae, and other unusual ‘helminths’ swarm and proliferate in the alveoli of the homonymous ‘vers’ since it is rather in those of the Fleurs du mal, more than in the prose of the Spleen de Paris (in spite of the reptilian dedication to Arsene Houssaye), that this infectious and contaminating swarming seems to happen. After a quick inventory of this poisonous micro bestiary, this article aims to reveal its symbolic and, above all, poetic significance, if we consider that Memento mori such as ‘Une charogne’ or ‘Le Flacon’ are also authentic poetic arts in which the oxymoric work of decomposition / recreation carried by these ‘infamous’ little creatures takes place. ‘From the vaporization and centralization of the Self. All is there’, says the first fragment of Mon cœur mis à nu. There is nothing like some ‘black battalions of larvae’ to perform this paradigmatic reversal of the putrefied and pulverized organic matter to the reconfigured and sublimated poetics.