Bone geminate serpents differ from the other types in many ways. Resembling skeletal serpents, with bones that glint like polished ivory, bone serpents do not need food to live, subsisting entirely from ambient magic; they hunt entirely for sport, and to train their young. This in turn has led them to being the most feared of all the geminate serpents.

A favorite ploy of the bone serpents is to lay still, playing dead and leaping to attack when curious creatures investigate, allowing them to surprise on 1-3 on a 1d6 surprise roll.

Uniquely, bone geminate serpents have no breath weapon, rather they have an innate magical ability that they may use up to their hit dice times per day, though they can only use it at most every other round. This ability turns the serpent’s bones into razor-sharp steel blades, giving it bonuses to its armor class and attack bonus as listed in the table below, and also a +3 damage bonus on its constriction attack.

While this ability is active, the constriction attack also counts as a magical weapon. Once every day a bone geminate serpent can cast raise dead on all creatures within a 30-foot radius of its body, the spell lasting for as many rounds as the serpent has hit dice, before the raised creatures once more fall dead. This is how bone geminate serpents train their offspring to fight. As bone geminate serpents constrict with sharp exposed bones, and have no need for live prey, their constriction attacks do real damage rather than subduing.