The jaculus is a stout, dun snake which grows about a foot long, up to a third of which is its serrated rattle. It possesses an unusual, cross-hatched ribcage that grants an insectile appearance when moving and the ability to lock itself rigid, rib-against-rib. The breed has a narcotic venom akin to that of the amphisbaena.
In the wild, a jaculus typically hunts birds, squirrels, and beetles among the tree branches. During the spring, they cluster above predators’ lairs, and fall upon prey much larger than what they can eat themselves, stiffening their bodies to drive their rattle deep inside. This fragile structure then breaks off and releases a flood of debilitating toxins while the serpent withdraws to safety. The poisoned animal is easy prey for the larger predator, and scavengers and insects drawn to the kill provide ample food for the jaculus and its newly hatched young.
Thaia-thaan’ag breeds jaculi and use them in their raids.