This is a large and robust elapid reptile characterized by its remarkable size within its genus, regularly reaching lengths of 80 to 120 centimeters, with exceptional specimens exceeding 140 centimeters. Its body is cylindrical, stout, and lacks a defined neck, ending in a short, tapered tail. The highly aposematic color pattern consists of triads of black rings (typically numbering 6 to 14 triads along the body). Each triad is composed of three black rings separated by two narrower white or yellowish intermediate rings, while the triads themselves are separated by wide, vibrant red rings. The head is distinct, featuring a black snout that extends backward, bordered by a pale transverse band across the prefrontal scales, and followed by a parietal region that varies from red to black depending on the individual, giving it a diagnostic facial mask.

Geographical distribution: This species is primarily distributed throughout the central regions of South America, covering large portions of northern and central Argentina (extending from the northernmost provinces down to northern Patagonia, including Mendoza, San Luis, and La Pampa), western Paraguay, southeastern Bolivia, and the southwestern corner of Brazil in the state of Mato Grosso do Sul. This geographic range aligns closely with the biogeographical boundaries of the Gran Chaco and the Río de la Plata basin.

Habitat: It primarily inhabits arid and semi-arid forested formations, savannas, and xerophytic shrublands associated with the Chaco biogeographical province. It exhibits a strong preference for loose, sandy, or clay-rich soils that facilitate its burrowing habits, as well as areas containing deep leaf litter, decaying logs, and natural rock crevices that provide shelter from extreme temperatures and environmental dehydration.

Feeding: It exhibits specialized ophiophagous feeding habits, meaning its diet is almost exclusively composed of other snakes, particularly smaller colubrids and false coral snakes. It also regularly preys upon amphisbaenians (commonly known as worm lizards), legless lizards, small lizards, and occasionally small rodents or fossorial invertebrates, which it actively hunts by tracking chemical cues in the soil.

Behavior: It is a highly fossorial, crepuscular, and nocturnal species, spending the vast majority of its life underground, within rodent burrows, or hidden beneath dense surface leaf litter. Although possessing an extremely potent neurotoxic venom capable of causing respiratory failure, it is generally docile and non-aggressive, preferring to escape when disturbed. When cornered, it displays a unique defensive behavior where it hides its head under its body coils and raises and curls its tail, mimicking a secondary head to divert predatory strikes away from its vital organs.

Reproduction: This species utilizes an oviparous reproductive strategy, with mating occurring during the spring and summer months, stimulated by rising temperatures and seasonal rainfall. Females lay a single annual clutch of 4 to 12 elongated, leathery eggs, which are buried in humid soil, abandoned ant nests, or decaying tree trunks that offer stable thermal conditions for incubation. The incubation period lasts approximately 60 to 75 days, after which the fully formed hatchlings emerge, already equipped with functional venom glands and fangs.

Conservation status: It is currently classified as Least Concern (LC) on global red lists due to its extensive geographical range. However, on a regional scale across several Argentine provinces and Chacoan zones, local populations are threatened by rapid habitat destruction, driven by heavy deforestation for agricultural expansion (primarily soybean monocultures) and cattle ranching, alongside direct persecution by humans due to its highly venomous nature.