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 copies of any nonlegendary creature that saddled