This clever loop turns a graveyard recursion engine into an infinite sacrifice machine by letting Sun Titan pull its own trigger conditions directly from the ashes. With Viscera Seer ready to sacrifice the Titan on demand, Necrogen Communion steps in as the crucial glue that intercepts the creature's demise, immediately bringing the Sun Titan back to the battlefield. That new entry triggers the Titan's own ability, which reaches back into the graveyard to retrieve Necrogen Communion and reattach it to the giant, leaving you free to repeat the entire cycle endlessly for infinite death triggers, enter-the-battlefield effects, and scry depth.