Mortuary + Skirk Prospector + Bolas's Citadel + Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel

Mortuary

Skirk Prospector

Bolas's Citadel

Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel

How it works

1. Activate Skirk Prospector by sacrificing it.
2. When Skirk Prospector dies, Mortuary and Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel trigger.
3. Resolve the Mortuary trigger, putting Skirk Prospector from your graveyard onto the top of your library.
4. Resolve the Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel trigger, causing you to gain 1 life and target opponent to lose 1 life.
5. Cast Skirk Prospector from the top of your library by paying 1 life.
6. Repeat.

This engine turns a humble Goblin into an infinite loop by using Bolas's Citadel to cast spells directly from the top of your library for life instead of mana. When you sacrifice Skirk Prospector for red mana, Mortuary catches it on the way to the graveyard and immediately places it right back onto the top of your library. Meanwhile, Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel watches the creature die and drains your opponent's life while simultaneously offsetting the life cost paid to recast your sacrifice outlet.