Is a large, robust dipsadid snake that typically reaches lengths between 6.5 and 10 feet (2 to 3 meters), with females generally being larger and heavier than males. Its dorsal coloration is highly variable, ranging from yellowish-brown to olive-green, overlaid with a pattern of dark brown or black spots and bands. A distinctive dark postocular stripe runs from behind the large, round-pupilled eyes down to the neck region. This species features an opisthoglyphous dentition, possessing enlarged rear fangs connected to Duvernoy´s gland, which secretes a mild to moderate necrotizing and anticoagulant venom used to subdue prey. Its most iconic anatomical feature is the ability to dorsoventrally flatten its neck by extending its elongated cervical ribs, creating a hood reminiscent of true cobras as a defensive display.

Geographical distribution: Occurs widely across the tropical and subtropical regions of South America. Its geographic range extends throughout major portions of Brazil (particularly within the Pantanal and Cerrado biomes), eastern Bolivia, the entirety of Paraguay, and northern Argentina, specifically in provinces such as Formosa, Chaco, and Corrientes.

Habitat: Is closely associated with lowland freshwater ecosystems. It is frequently encountered in wetlands, marshes, swamps, seasonally flooded savannas, and along the margins of slow-moving rivers and streams. While predominantly semiaquatic, it also utilizes adjacent gallery forests, damp grasslands, and agricultural fields where moisture levels remain high.

Feeding: Functions as a generalist and highly opportunistic predator. Its diet is remarkably diverse, consisting of fish, amphibians (especially large toads of the genus Rhinella), small mammals, wading birds, and other reptiles, including lizards and smaller snake species. It employs a combination of physical constriction and the injection of its toxic saliva to quickly incapacitate and swallow its prey.

Behavior: Exhibits primarily diurnal activity patterns and is an exceptionally skilled swimmer, often foraging actively in shallow waters. When threatened, it performs an impressive defensive display by raising the front third of its body, spreading its hood, and producing loud hissing sounds. Despite this aggressive appearance, it is generally non-confrontational and prefers to escape, biting only as a last resort if cornered or physically restrained.

Reproduction: Is an oviparous reptile with reproductive cycles usually synchronized with the warm, wet seasons of spring and summer. Females lay clutches consisting of 10 to 30 eggs, selecting nesting sites with high humidity, such as decomposing vegetation or hollow logs, to prevent desiccation. The incubation period lasts between 60 and 80 days, after which the neonates emerge at approximately 12 to 15 inches in length, fully independent and capable of displaying the characteristic hooding defense immediately.

Conservation status: Is categorized as Least Concern (LC) on the IUCN Red List due to its extensive geographical distribution and stable overall populations. However, localized declines occur due to habitat fragmentation, wetland drainage, pesticide contamination, and direct persecution by humans who mistake it for a highly lethal venomous snake or fear its defensive posture.