Lightning Runner and Infinite Reflection on the battlefield.
Infinite Reflection attached to Lightning Runner.
You control at least three other nontoken creatures.
Steps
Declare Lightning Runner and three other creatures as attackers, triggering each of their abilities.
Resolve the first Lightning Runner trigger, causing you to get ({E} magic symbol) ({E} magic symbol) and not pay for an additional combat phase.
Repeat step 2 two additional times.
Resolve the final Lightning Runner trigger, causing you to get ({E} magic symbol) ({E} magic symbol) and pay eight ({E} magic symbol) to untap all creatures you control and to get an additional combat phase after this one.