Yore-Tiller Nephilim, Port Razer, and Phyrexian Altar

Prerequisites

• Yore-Tiller Nephilim on the battlefield
• Port Razer in the graveyard
• Phyrexian Altar on the battlefield
• Yore-Tiller Nephilim does not have summoning sickness
• An opponent is unable to block creatures you control

Steps

1. Declare Yore-Tiller Nephilim as an attacker
2. Yore-Tiller Nephilim triggers, returning Port Razer from your graveyard onto the battlefield tapped and attacking
3. Deal combat damage with Port Razer and Yore-Tiller Nephilim
4. Port Razer triggers, untapping each creature you control and causing you to get an additional combat phase after this one
5. Activate Phyrexian Altar by sacrificing Port Razer, adding one mana of any color
6. Repeat each combat phase

Results

• Infinite combat damage
• Infinite combat phases
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana creatures you control can produce
• Infinite sacrifice triggers
• Infinite untap of creatures you control