One of the best known Etruscan mirror engravings shows Uni performing an act found nowhere in Greek myth involving Hera: seated and exposing her breast, she suckles the fully grown, bearded hero Hercle, the Etruscan Heracles, an image art historians read as a formal act of divine adoption rather than literal infant nursing, a ritual gesture by which an adult could be symbolically reborn as the child, and therefore the kin, of a goddess or powerful patron. The motif of adoption through symbolic nursing of an adult is attested elsewhere in the ancient Mediterranean world as a recognized legal or ritual fiction for creating kinship where none existed by birth, and the Etruscan mirror applies the same underlying idea to explain how the originally Greek hero Heracles, imported into Etruscan religion as Hercle, could be fully naturalized into the Etruscan divine family through Uni herself, the queen of the pantheon, rather than remaining a foreign import grafted awkwardly onto native belief.
The scene has no clear equivalent in the Greek myths of Hera, who is Heracles's tormentor rather than his adoptive mother in the standard Greek tradition, making this specifically an Etruscan reworking of the borrowed hero's relationship to the chief goddess rather than a straightforward copy of any Greek original. Etruscan mirror engravers frequently reshaped imported Greek mythological figures to fit native Etruscan theological logic in exactly this way, and Uni's nursing of the adult Hercle stands as one of the clearest surviving examples of that reworking, transforming a borrowed hero's fraught Greek relationship with Hera into an Etruscan story of formal, dignified adoption into divinity.