When King Yazdegerd the Sinner was afflicted with a relentless, agonizing nasal hemorrhage that no physician could stem, a wise Mobad stepped forward and warned him: 'O King, you have strayed from the path of the Almighty, believing you could evade the clutch of death. Your only salvation lies in journeying toward the Spring of Su, humbling yourself upon its warm earth, and weeping before the pure Creator.' The King took the priest's counsel to heart and set forth in a procession of three hundred litters, tormented day and night by the stream of blood flowing from his nose until they neared the mystical waters.
Upon arriving at the shore of the Spring of Su, Yazdegerd dismounted his litter, applied some of the sacred water to his head, and called upon Yazdan, the Bestower of All Goodness. In an instant, the hemorrhaging ceased, and his pain evaporated. Yet, instead of offering heartfelt gratitude to the Divine, the King was instantly overtaken by monstrous pride. He scoffed, questioning why he had humbled himself so low, and attributed his sudden recovery entirely to his own strength and majesty.
No sooner had he surrendered to vanity than a cosmic marvel emerged from the depths of the blue waters: a magnificently sculpted white Water Horse, compact of limb and broad of rump, snorting with the fury of a wild lion, possessing dark eyes, foam-flecked lips, and black, solid hooves. Yazdegerd ordered his warriors to capture the beast, but the host and shepherds stood paralyzed in absolute dread of the dragon-like steed. Enraged by their fear, the King took up the bridle and saddle himself and approached the creature. Miraculously, the steed stood motionlessly, allowing the King to bit him, cinch the saddle tight, and prepare him for riding.
However, as Yazdegerd stepped behind the horse to tie its tail, the rock-hooved beast roared like thunder and delivered a terrible double-kick straight to the King's chest. Yazdegerd fell to the earth, his crown rolling into the dust as his spirit departed his shattered frame. The wild Water Horse then vanished like a sudden gust of wind, plunging back into the azure spring, leaving the spectators spellbound by the divine spectacle.
A immense wail rose from the army as they tore their garments and cast dust upon their heads. The Mobad carefully embalmed the royal corpse with camphor and musk, wrapped it in fine silk, and sealed it within a golden coffin upon a sandalwood litter to be transported to Pars. Thus did fate remind humankind that worldly dominion is fleeting, and that true power lies only in reverence to the Divine.