Cast Traveling Plague by paying 3, attaching it to another creature you control.
When Traveling Plague enters, Archon of Sun's Grace triggers, creating a creature token.
Activate Viscera Seer by sacrificing the creature Traveling Plague is attached to.
When the creature dies, Traveling Plague triggers, returning itself from your graveyard to the battlefield attached to the token created in step 2.
When Traveling Plague enters, Archon of Sun's Grace triggers, creating a creature token.
Resolve the Viscera Seer ability.
Repeat from step 3.
This clever loop turns a creeping curse into a self-sustaining engine by exploiting Traveling Plague's built-in recycling clause: when the enchanted creature leaves the battlefield, the Aura returns directly to the battlefield. By using Viscera Seer to sacrifice the host creature on demand, you send the Plague to the graveyard, triggering its return to a brand-new target. Meanwhile, the watchful presence of Archon of Sun's Grace transforms every single re-entry of the enchantment into a fresh Pegasus token, which immediately steps up as the next sacrificial victim for Viscera Seer to devour.