Sun Titan, Grimgrin, Corpse-Born, and Unholy Indenture

Prerequisites

• Sun Titan on the battlefield
• Grimgrin, Corpse-Born on the battlefield
• Unholy Indenture on the battlefield

Steps

1. Activate Grimgrin by sacrificing Sun Titan
2. When Sun Titan dies, Unholy Indenture triggers, returning Sun Titan from your graveyard to the battlefield
3. When Sun Titan enters, it triggers, returning Unholy Indenture from your graveyard to the battlefield attached to Sun Titan
4. Resolve the Grimgrin ability
5. Repeat

Results

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