In Hindu mythology, the thunderbolt weapon wielded by the god Indra is called the vajra.
The vajra is one of Indra’s principal attributes and represents irresistible force, authority, and the power of storms. In the Rigveda, Indra uses it against Vritra, a serpent or dragon associated with drought, to release the waters and restore cosmic order.
Later Hindu traditions describe the vajra as being made from the bones of the sage Dadhichi, who sacrificed himself so the gods could forge a weapon strong enough to defeat the demon forces threatening them. This story links the weapon’s power with self-sacrifice.
The vajra is sometimes confused with Shiva’s trishula or Vishnu’s Sudarshana Chakra. Those are different divine weapons: the trishula is a three-pronged spear, while the Sudarshana Chakra is a discus. In Buddhist traditions, vajra symbolism also became important, but its earliest major Hindu association is with Indra.