Anzrag, the Quake-Mole, and Darksteel Mutation

Prerequisites

• Anzrag, the Quake-Mole on the battlefield
• Darksteel Mutation in hand
• An opponent controls exactly one creature
• Anzrag does not have summoning sickness
• available

Steps

1. Activate Anzrag by paying , causing opponents to block Anzrag if able this turn
2. Cast Darksteel Mutation for targeting the only creature an opponent controls
3. Resolve Darksteel Mutation, turning the enchanted creature into a 0/1 Insect artifact creature with indestructible
4. Declare Anzrag as an attacker, attacking the opponent who controls the enchanted creature
5. The opponent is forced to block Anzrag with the enchanted creature, triggering Anzrag, untapping all creatures you control and causing you to get an additional combat phase after this one
6. Repeat from step 4

Results

• Infinite combat phases
• Infinite untap of creatures you control
• Infinite mana creatures you control can produce