Moritte of the Frost, Staff of Eden, Vault's Key, and Arcbound Crusher

Prerequisites

• Moritte of the Frost in hand or in the command zone
• Staff of Eden, Vault's Key on the battlefield
• Arcbound Crusher on the battlefield
• plus enough mana to pay for commander tax, if applicable available

Steps

1. Cast Moritte of the Frost from your hand or from the command zone by paying plus commander tax, if applicable, choosing to have it enter the battlefield as a copy of Staff of Eden
2. Put Moritte of the Frost into your graveyard due to the legend rule
3. Morrite of the Frost's enters-the-battlefield ability and Arcbound Crusher trigger
4. Resolve the Arcbound Crusher trigger, putting a +1/+1 counter on it
5. Resolve the Moritte of the Frost trigger, returning Moritte of the Frost from your graveyard to the battlefield as a copy of Staff of Eden
6. Repeat from step 2

Results

• Infinite +1/+1 counters on Arcbound Crusher