Calamity triggers, creating a tapped and attacking copy of
Port Razer, and repeating the process once for any nonlegendary creature that saddled
Calamity this turn.
Deal combat damage using the
Port Razer token(s).
Each
Port Razer who has not attacked the opponent this turn triggers, causing you to untap each creature you control and to get that many additional combat phases after this one.
Repeat from step 2 each combat phase.
Results
Infinite combat damage.
Infinite combat phases.
Infinite creature tokens.
Infinite ETB.
Infinite mana creatures you control can produce.
Infinite untap of creatures you control.
Infinite LTB.
Infinite sacrifice triggers.
Infinite death triggers.
Infinite copies of nonlegendary creatures you control.