Gravecrawler, Rooftop Storm, and Grimgrin, Corpse-Born

Prerequisites

• Gravecrawler on the battlefield
• Rooftop Storm on the battlefield
• Grimgrin, Corpse-Born on the battlefield

Steps

1. Activate Grimgrin's ability by sacrificing Gravecrawler, untapping Grimgrin and putting a +1/+1 counter on Grimgrin
2. Cast Gravecrawler from your graveyard by paying
3. Repeat

Results

• Infinite +1/+1 counters on Grimgrin
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers
• Infinite storm count