Dualcaster Mage, Leonardo's Technique, and Hammerhead, Maggia Boss

Prerequisites

• Dualcaster Mage in hand
• Leonardo's Technique in hand
• Hammerhead, Maggia Boss on the battlefield
• available

Steps

1. Cast Leonardo's Technique by paying its mana cost, targeting any applicable target
2. Holding priority, cast Dualcaster Mage by paying its mana cost
3. When Dualcaster Mage enters, it triggers, targeting Leonardo's Technique
4. Holding priority, activate Hammerhead by sacrificing Dualcaster Mage
5. Resolve the Dualcaster Mage trigger, copying Leonardo's Technique, with the copy targeting Dualcaster Mage Resolve the Leonardo's Technique copy, returning Dualcaster Mage from your graveyard to the battlefield
6. Repeat from step 3

Results

• Infinite +1/+1 counters on a creature
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite magecraft triggers
• Infinite recursion of creature cards in your graveyard