Means ("snake"), Vritra was also known in the Vedas as Ahi cognate with Azhi Dahaka of Zoroastrian mythology and he is said to have had three heads. In the early Vedic religion, Vritra (Vṛtra वृत्र "the enveloper"), is an Asura and also a serpent or dragon, the personification of drought and adversary of Indra. Vritra was also known in the Vedas as Ahi ("snake"). He appears as a dragon blocking the course of the rivers and is heroically slain by Indra.