Cast Incarnation Technique by paying its mana cost, targeting any applicable target.
Holding priority, cast Dualcaster Mage by paying its mana cost.
When Dualcaster Mage enters, it triggers, targeting Incarnation Technique.
Holding priority, activate Shilgengar by sacrificing Dualcaster Mage.
Resolve the Dualcaster Mage trigger, copying Incarnation Technique, with the copy targeting Dualcaster Mage
Resolve the Incarnation Technique copy, returning Dualcaster Mage from your graveyard to the battlefield.
Repeat from step 3.
This clever loop hinges on Shilgengar, Sire of Famine serving as both the sacrificial engine that turns your creatures into Blood tokens and the ultimate payoff to reanimate your whole graveyard. By casting Incarnation Technique, you set up a target in the graveyard while demonstrating it, but the real magic begins when you drop Dualcaster Mage with flash. As Dualcaster Mage enters the battlefield, its triggered ability copies the spell, and by sacrificing the Mage to Shilgengar's ability in response, you ensure it is safely in the graveyard ready to be brought back. The resolving copy of Incarnation Technique then loops Dualcaster Mage right back onto the battlefield, creating an endless cycle of sacrifices, self-milling, and a mountain of Blood tokens.