Tlalocoatls were massive, serpentine creatures with turquoise-blue scales. They had no legs or wings, and had a head on both ends of their body. One head was like a jaguar's, and the other was like a snake.
Both heads of the tlalocoatl had a breath weapon; the snake head breathed a cone of ice crystals, and the jaguar head breathed a cloud of scalding-hot steam. When used together, the breath weapons combined to create rain. The serpent head also had venomous fangs, and both heads could attack by biting.
Tlalocoatls also had the magical ability to fly, and could cast other magic spells. They could control the weather, causing floods and droughts as well as ending them.
Tlalocoatls were dangerous, capricious creatures that lived in mountain caves. They worshiped the god Azul fervently, and sometimes acted as his servants. They were solitary creatures, producing offspring only with Azul's permission. Most tlalocoatls died while still young, but they could live as long as 675 years.
Tlalocoatls ate such interesting materials as turquoise stone, cocoa beans, and jade; they also enjoyed eating meat, particularly that of young animals and human children. Tlalocoatls also drank great quantities of water, and were known to attack chacs in order to get the water they contained.
Although they weren't particularly greedy, rain serpents were known to hoard items such as coral, gold dust, jade, turquoise, and magical items.