The cockatrice was first depicted in the twelfth century in Pliny's Natural History and became a popular figure in Elizabethan poetry. It appears as a large rooster with a reptilian tail very similar to the basilisk, however the cockatrice had wings and can usually fly. It is born when an egg laid by a cock (male chicken) is incubated by a snake or toad.
In a similar way to its cousin the basilisk, the cockatrice has the ability to turn a person to stone or kill them by looking at them, although it is sometimes by touching them or breathing on them. The cockatrice is hard to kill, one of the only certain ways to kill it is to have it look at its own reflection. Although it will also die if it hears a rooster crow, the cockatrice's ability to petrify those that look at it will remain in a similar way to Medusa.
According to the folklore of Wherwell in England, a cockatrice once terrorized the village until they managed to trap the beast in the dungeons beneath Wherwell Priory. Land was offered to the man who could slay the beast, and many tried and failed until a man named Green offered to try. Green lowered a mirror into the dungeon and the cockatrice exhausted itself battling its own reflection, at which point Green attacked and killed it.
"Origin: North Africa. Like a basilisk, they can turn you to stone. They are created when an egg laid by a rooster is hatched by a toad. It appears as a four-legged rooster with a snake's tail."
—Shin Megami Tensei A-Mode DDS dictionary
Shin Megami Tensei IMAGINE
"A monster born from a rooster's egg (or a hen's egg sired by a toad) that is incubated by a snake. It resembles a cross between a chicken and a snake. The Cockatrice is closely related to the Basilisk, and the two are sometimes seen as male and female version of the same creature. Its breath is poison, and those who see or touch it are turned to stone. The Cockatrice's chicken-like appearance is thought to be a later derivation from word "cock" (rooster) in its name."
—Shin Megami Tensei IMAGINE compendium
Cockatrice can be contracted with on Nakano and Ueno field. Negotiating with the inexperienced variant that spawns on Ueno field has a chance of giving the player the item necessary to summon the field boss Merciless Queen Hecate.
DemiKids Light & Dark
"Bird-like demon born from an unusual egg. Everything it stares at turns to stone."