Holding priority, cast Dualcaster Mage by paying its mana cost.
When Dualcaster Mage enters, it triggers, targeting Dread Return.
Holding priority, activate Viscera Seer by sacrificing Dualcaster Mage.
Resolve the Dualcaster Mage trigger, copying Dread Return
Resolve the Dread Return copy, returning Dualcaster Mage from your graveyard to the battlefield.
Repeat from step 3.
This elegant loop turns a graveyard recursion spell into an infinite engine by continually recycling its own catalyst. You cast Dread Return to kick things off, then drop Dualcaster Mage to copy it mid-flight while Viscera Seer sits patiently waiting to sacrifice the Mage. Because the copy of Dread Return resolves first and plucks Dualcaster Mage straight back out of your graveyard, you can endlessly repeat the sacrifice and copy cycle to trigger an avalanche of deaths and creature enters-the-battlefield events, all while smoothing your draws with infinite scry 1s.