Tradition: Greek Mythology, Roman Mythology, Italian Mythology
Alternative Names: Jaculus, Iaculus, Javelin Snake
Category: Dragon
The Myth
The Jaculus is a small mythical serpent or dragon, sometimes depicted with wings and occasionally with front legs. It was a creature that attacked from above, hiding among the branches of trees before launching itself at unsuspecting victims like a living javelin.
Its name comes from the Latin word for “thrown,” reflecting the extraordinary force with which the serpent hurled itself through the air. Rather than relying upon venom, the Jaculus killed through the sheer impact of its body. When it struck a victim, the force of the collision caused a fatal wound.
The creature was feared precisely because its attack could come without warning. Hidden high in the branches, it would suddenly spring from its perch and fly through the air toward its target. Pliny described the serpent as being dangerous not merely to a person’s feet, but as something that could actually fly through the air as though launched from a weapon.
Lucan likewise described the Jaculus as a deadly attacker, emphasizing that it was the wound inflicted when the creature struck that caused death, rather than poison.
The same strange idea of a serpent used as a living projectile appears in Malagasy folklore in the tale of the fandrefiala. This small snake was said to carefully calculate its trajectory before hurling itself at a victim with such force that the impact could break a metal pot, killing both the snake and its target.
The Jaculus also appears in the Old Norse Yngvars saga viðfǫrla, where the creature is described not as a tiny serpent but as an enormous dragon. Medieval European tradition likewise preserved the creature as the “javelin-snake,” a serpent that launches itself from trees, as recorded in the Aberdeen Bestiary.
Sources
“Jaculus.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation. Accessed September 26, 2026. https://en.wikipedia.org/wiki/Jaculus