Leonin Relic-Warder, Rescue Skiff, and Grimgrin, Corpse-Born

Prerequisites

• Leonin Relic-Warder in hand
• Rescue Skiff on the battlefield
• Grimgrin, Corpse-Born on the battlefield
• available

Steps

1. Cast Leonin Relic-Warder by paying
2. When Leonin Relic-Warder enters, its first ability triggers, exiling Rescue Skiff
3. Activate Grimgrin by sacrificing Leonin Relic-Warder
4. When Leonin Relic-Warder dies, its second ability triggers, returning Rescue Skiff from exile to the battlefield
5. When Rescue Skiff enters, it triggers, returning Leonin Relic-Warder from your graveyard to the battlefield
6. When Leonin Relic-Warder enters, its first ability triggers, exiling Rescue Skiff
7. Resolve the Grimgrin ability from step 3
8. Repeat from step 3

Results

• Infinite +1/+1 counters on a creature
• Infinite artifact ETB
• Infinite artifact LTB
• Infinite artifact sacrifice triggers
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers