Activate Anzrag by paying ({3} magic symbol) ({G} magic symbol) ({G} magic symbol) ({R} magic symbol) ({R} magic symbol) , causing opponents to block Anzrag if able this turn.
Cast Darksteel Mutation for ({1} magic symbol) ({W} magic symbol) targeting the only creature an opponent controls.
Resolve Darksteel Mutation, turning the enchanted creature into a 0/1 Insect artifact creature with indestructible.
Declare Anzrag as an attacker, attacking the opponent who controls the enchanted creature.
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.