Dualcaster Mage, and Irenicus's Vile Duplication

Prerequisites

• Dualcaster Mage in hand
• Irenicus's Vile Duplication in hand
• You control at least one creature
• You have enough mana to cast Irenicus's Vile Duplication available

Steps

1. Cast Irenicus's Vile Duplication by paying its mana cost, targeting a creature you control
2. Holding priority, cast Dualcaster Mage by paying
3. When Dualcaster Mage enters the battlefield, it triggers, copying Irenicus's Vile Duplication, targeting Dualcaster Mage
4. Resolve the copy of Irenicus's Vile Duplication, creating a token copy of Dualcaster Mage
5. Repeat from step 3

Results

• Infinite creature tokens
• Infinite ETB
• Infinite magecraft triggers