Garshasp
Garshāsp (گرشاسپ) is the name of a monster-slaying hero in Iranian mythology. The Avestan form of his name is Kərəsāspa and in Middle Persian his name is Kirsāsp.
Kərəsāspa / Kirsāsp in Zoroastrian literature
In the Zoroastrian religious text of the Avesta, Kərəsāspa appears as the slayer of ferocious monsters, including the Gandarəβa and the Aži Sruvara. In later Zoroastrian texts Kirsāsp is revived at the end of the world to defeat the monster Dahāg.
Kərəsāspa is the son of Θrita and belongs to the Sāma family. Θrita is originally the name of a deity; cf. the Vedic Trita.
Kərəsāspa and the Aži Sruvara
According to the Zoroastrian holy book, Avesta, Kərəsāspa once stopped on a hill to cook his midday meal. Unknown to Kərəsāspa, the hill was actually the back of a dragon—the Aži Sruvara. As the heat from Kərəsāspa's fire woke the dragon, it woke up, overturning Kərəsāspa's kettle. Kərəsāspa fled, but returned to slay the dragon.
Later texts, the Persian Rivayat and Pahlavi Rivayat, add more details. According to them, the Az ī Srūwar was a dragon with horns, with huge eyes and ears, and teeth upon which the men it had eaten could be seen impaled. It was so long that Kərəsāspa ran along its back for half a day before he reached its head, struck it with his mace, and killed it.