Saffi Eriksdotter, Sister Hospitaller, and Grimgrin, Corpse-Born

Prerequisites

• Saffi Eriksdotter on the battlefield
• Sister Hospitaller on the battlefield
• Grimgrin, Corpse-Born on the battlefield

Steps

1. Activate Saffi by sacrificing it, targeting Sister Hospitaller Activate Grimgrin by sacrificing Sister Hospitaller When Sister Hospitaller dies, Saffi triggers, returning Sister Hospitaller from your graveyard to the battlefield
2. When Sister Hospitaller enters, it triggers, returning Saffi from your graveyard to the battlefield
3. Resolve the Grimgrin ability
4. Repeat

Results

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