Infinite combat damageInfinite combat phasesInfinite death triggersInfinite creature ETBInfinite creature LTBInfinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite untap of creatures you control
How it works
Declare Phantom Steed as an attacker, attacking any opponent that is unable to block and kill your creatures.
Phantom Steed's second ability triggers, creating a tapped and attacking copy of Port Razer.
Deal combat damage with Phantom Steed and Port Razer.
Port Razer triggers, causing you to untap all creatures you control and get an additional combat phase after this one.
At the end of your combat phase, Phantom Steed triggers, causing you to sacrifice the Port Razer token.