This loop hinges entirely on the passive enchantment-welcoming power of Secret Arcade // Dusty Parlor, which reclassifies every nonland permanent and spell you control as an enchantment. Because of this sweeping transformation, when you cast Ajani's Chosen, it enters the battlefield as an enchantment and immediately triggers its own ability to manufacture a 2/2 white Cat creature token. That newly arrived token also benefits from Secret Arcade // Dusty Parlor, entering as an enchantment itself and thus triggering Ajani's Chosen all over again in an unstoppable, self-sustaining loop that forces a game-ending draw.