Mortuary + Phyrexian Altar + Serrated Scorpion + Gwenom, Remorseless

Mortuary

Phyrexian Altar

Serrated Scorpion

Gwenom, Remorseless

How it works

1. Activate Phyrexian Altar by sacrificing Serrated Scorpion.
2. When Serrated Scorpion dies, it and Mortuary triggers.
3. Resolve the Mortuary trigger, putting Serrated Scorpion from your graveyard onto the top of your library.
4. Resolve the Serrated Scorpion trigger, causing you to gain 2 life and dealing 2 damage to each opponent.
5. Cast Serrated Scorpion from the top of your library by paying 1 life due to Gwenom.
6. Repeat.

This lethal loop turns Phyrexian Altar into an engine for infinite damage and life by leveraging Mortuary to constantly recycle your sacrificed threats. Whenever Serrated Scorpion is fed to the Altar, Mortuary immediately intercepts it on the way to the graveyard and stacks it right back on top of your library. That is where Gwenom, Remorseless comes in: its attack-triggered static ability lets you cast the Scorpion directly from the top of your library, paying life instead of mana which is easily offset by the life gained from the Scorpion's own death trigger.