Saffi Eriksdotter, Grimgrin, Corpse-Born, and Karmic Guide

Prerequisites

• Saffi Eriksdotter on the battlefield
• Grimgrin, Corpse-Born on the battlefield
• Karmic Guide on the battlefield

Steps

1. Activate Saffi by sacrificing it, targeting Karmic Guide Activate Grimgrin by sacrificing Karmic Guide When Karmic Guide dies, Saffi triggers, returning Karmic Guide from your graveyard to the battlefield
2. When Karmic Guide 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