Havengul Lich, Grimgrin, Corpse-Born, Necroduality, and Relic of Legends

Prerequisites

• Havengul Lich on the battlefield
• Grimgrin, Corpse-Born on the battlefield
• Necroduality on the battlefield
• Relic of Legends on the battlefield

Steps

1. Activate Relic of Legends's last ability by tapping Grimgrin, adding one mana
2. Activate Grimgrin by sacrificing the zombie castable for one mana, untapping Grimgrin and putting a +1/+1 counter on it
3. Activate Relic of Legends's last ability by tapping Grimgrin, adding one mana
4. Activate Havengul Lich by paying , allowing you to cast the zombie castable for one mana from your graveyard this turn
5. Cast that zombie spell from your graveyard by paying it mana cost
6. When you cast that zombie or when it enters, Necroduality triggers, creating a creature token
7. Activate Grimgrin by sacrificing the creature token, untapping Grimgrin and putting a +1/+1 counter on it
8. Repeat

Results

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