Cockatrice

In medieval bestiary and later compilations the cockatrice is said to originate from an abnormal incubation: a rooster's (so‑called 'cock') egg hatched by a toad or snake (accounts vary). This legendary origin—recorded in medieval compilations and traced in learned commentaries that conflate classical terms (e.g., basilisk/ichneumon) with bestiary motifs—frames the creature as a pathological inversion of normal animal generation and as a product of improper incubation within folk and learned imaginations.

Sources describe a composite beast: essentially a two‑legged dragon/wyvern or serpent‑bodied animal bearing a rooster's head with comb and wattles. Variants stress scales on the body, bat‑like wings, a tail likened to an asp with a sting, and a forked tongue; richly detailed literary depictions (cited in later fiction) add size and color notes but specific dimensions are part of individual literary descriptions rather than a single canonical measurement.

Legendary attributions in bestiary and later literary sources credit the cockatrice with a deadly effect by gaze, and in some accounts also by touch or breath. Medieval writers and later compilers repeat claims that its look can kill, and folk/household remedies and literary texts treat this as a characteristic threat. The creature was often conflated with the basilisk in translation and commentary, so accounts of its powers overlap with basilisk traditions in some sources.