Port Razer + Splinter Twin

Port Razer
Splinter Twin

Requires
All permanents on the battlefield. Splinter Twin attached to Port Razer. Port Razer does not have summoning sickness. An opponent is unable to block Port Razer.
Steps
  1. Activate Port Razer's ability from Splinter Twin by tapping it, creating a token copy of Port Razer with haste
  2. Declare the newest Port Razer copy as an attacker
  3. When the token copy of Port Razer deals combat damage to an opponent, it triggers, untapping all your creatures and creating an additional combat phase after this one
  4. Repeat
Results
Infinite damage. Infinite creature tokens with haste. Infinite combat phases. Infinite combat damage. Infinite ETB. Infinite LTB. Infinite untap of creatures you control.