This clever loop begins when you cast Stolen Identity to create a token of an artifact or creature, but before it can resolve, you slide Dualcaster Mage onto the stack with flash. When Dualcaster Mage enters the battlefield, its triggered ability targets the original Stolen Identity, spawning a fresh copy that targets Dualcaster Mage itself to continually churn out endless token copies of Dualcaster Mage. Because every newly minted token copy enters the battlefield ready to repeat the process, you generate infinite creature entrance triggers, infinite magecraft triggers, and an overwhelming army of mage tokens.