Umbral Mantle, and Fanatic of Rhonas

Prerequisites

• Umbral Mantle on the battlefield
• Fanatic of Rhonas on the battlefield

Steps

1. Activate Fanatic of Rhonas's second ability by tapping it, adding
2. Activate Fanatic of Rhonas using the ability from Umbral Mantle by paying and untapping it, giving it +2/+2 until end of turn
3. Repeat

Results

• Infinite green mana
• Infinite untap of creatures you control
• Infinite mana creatures you control can produce
• Infinitely large creature until end of turn