Agatha's Soul Cauldron, Grumgully, the Generous, Krenko, Mob Boss, and Concordant Crossroads

Prerequisites

• Agatha's Soul Cauldron on the battlefield
• Grumgully, the Generous on the battlefield
• Krenko, Mob Boss in exile
• Concordant Crossroads on the battlefield
• You control a creature with a +1/+1 counter on it

Steps

1. Activate a creature with a +1/+1 counter on it, creating a 1/1 red Goblin creature token
2. The 1/1 Goblin token enters with a +1/+1 counter on it due to Grumgully's ability
3. Repeat

Results

• Infinite ETB
• Infinite tapped creature tokens