Dualcaster Mage, Grimgrin, Corpse-Born, and Unearth

Prerequisites

• Dualcaster Mage in hand
• Grimgrin, Corpse-Born on the battlefield
• Unearth in hand
• available

Steps

1. Cast Unearth 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 Unearth
4. Holding priority, activate Grimgrin by sacrificing Dualcaster Mage
5. Resolve the Dualcaster Mage trigger, copying Unearth, with the copy targeting Dualcaster Mage Resolve the Unearth 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