Umbral Mantle, and Axebane Guardian

Prerequisites

• Umbral Mantle on the battlefield
• Axebane Guardian on the battlefield

Steps

1. Activate Axebane Guardian by tapping it, adding at least three mana of any color
2. Activate Axebane Guardian by paying and untapping it, giving it +2/+2 until end of turn
3. Repeat

Results

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