How can you create a combo with Phantom Steed, Port Razer?
user
[START OF COMBO]This combo can be formed with Phantom Steed, Port Razer

Color identity: UR
Mana cost: 
Steps:
  1. Declare Phantom Steed as an attacker, attacking any opponent that is unable to block and kill your creatures.
  2. Phantom Steed's second ability triggers, creating a tapped and attacking copy of Port Razer.
  3. Deal combat damage with Phantom Steed and Port Razer.
  4. Port Razer triggers, causing you to untap all creatures you control and get an additional combat phase after this one.
  5. At the end of your combat phase, Phantom Steed triggers, causing you to sacrifice the Port Razer token.
  6. Repeat each combat phase.[END OF COMBO STEPS]

Result:
  - Infinite combat damage
  - Infinite combat phases
  - Infinite death triggers
  - Infinite enters the battlefield
  - Infinite leaves the battlefield
  - Infinite mana creatures you control can produce
  - Infinite sacrifice triggers
  - Infinite untap of creatures you control[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Phantom Steed must be on the battlefield
  - Port Razer must be exiled
  - Phantom Steed does not have summoning sickness.
  - An opponent is unable to block and kill creatures you control.
[END OF COMBO PREREQUISITES]
assistant