Emrakul, the Exigent Doom, and Karakas

Prerequisites

• Emrakul, the Exigent Doom in hand
• Karakas on the battlefield

Steps

1. Activate any number of lands by tapping them, adding at least Cast Emrakul by paying plus commander tax if applicable
2. Emrakul triggers, untapping all lands you control
3. Resolve Emrakul
4. Then, activate Karakas's second ability by tapping it, returning Emrakul from the battlefield to your hand
5. Repeat

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite mana lands you control can produce
• Infinite storm count
• Infinite untap of lands you control