Holding priority, cast Dualcaster Mage by paying its mana cost.
When Dualcaster Mage enters, it triggers, targeting Victimize.
Holding priority, activate Goblin Bombardment by sacrificing Dualcaster Mage.
Resolve the Dualcaster Mage trigger, copying Victimize
Resolve the Victimize copy, sacrificing a creature and returning Dualcaster Mage and another creature from your graveyard to the battlefield.
Repeat from step 3.
This clever loop kicks off when you cast Victimize to sacrifice a creature and target two cards in your graveyard, setting the stage for Dualcaster Mage to enter with its flash speed and copy the original sorcery in mid-air. By sacrificing Dualcaster Mage to Goblin Bombardment in response to its own copy trigger, you send the Mage right back to the graveyard so that the resolving copy of Victimize can pluck it and another creature right back onto the battlefield. This creates an endless cycle where Goblin Bombardment turns your recurrent sacrifices into infinite damage, effortlessly weaponizing the Mage's recursive entry into a game-ending loop.