Mortuary + Bolas's Citadel + Bartolomé del Presidio + Serrated Scorpion

Mortuary

Bolas's Citadel

Bartolomé del Presidio

Serrated Scorpion

How it works

1. Activate Bartolomé del Presidio 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. Resolve the Bartolomé del Presidio ability.
6. Cast Serrated Scorpion from the top of your library by paying 1 life due to Bolas's Citadel.
7. Repeat.

This loop turns your library into an endless cycle of sacrifice and rebirth by letting Bolas's Citadel cast the same card straight off the top over and over. Whenever Bartolomé del Presidio demands a sacrifice, Serrated Scorpion happily steps up to the plate, triggering its own death ability to drain your opponents and gain you life to offset the cost of recasting it. Meanwhile, Mortuary catches the scorpion on its way to the graveyard and quietly tucks it right back onto the top of your library. Because Bolas's Citadel allows you to play spells directly from that top spot—substituting life payments for mana costs—the loop feeds itself indefinitely until your opponents are whittled down to nothing.