Port Razer, and Splinter Twin

Prerequisites

• Port Razer on the battlefield
• Splinter Twin 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 combat damage
• Infinite combat phases
• Infinite creature tokens with haste
• Infinite damage
• Infinite ETB
• Infinite LTB
• Infinite mana creatures you control can produce
• Infinite untap of creatures you control