Mortuary + Vivien, Monsters' Advocate + Stonecoil Serpent

Mortuary

Vivien, Monsters' Advocate

Stonecoil Serpent

How it works

1. Cast Stonecoil Serpent either from your hand or from the top of your library by paying 0.
2. Stonecoil Serpent enters the battlefield and dies as a state-based action due to having zero toughness.
3. Mortuary triggers, putting Stonecoil Serpent on top of your library from your graveyard.
4. Repeat.

This loop turns a seemingly harmless mechanical interaction into a relentless engine by leveraging Stonecoil Serpent's unique ability to be cast for zero mana. As soon as the Serpent enters the battlefield with zero toughness, it instantly dies, which immediately triggers Mortuary to place it right back on top of your library. From there, Vivien, Monsters' Advocate steps in to provide the crucial top-deck access, letting you look at the top of your library and continuously recast the Serpent for free to rack up infinite death triggers, enter-the-battlefield effects, and storm count.