Mortuary + Amareth, the Lustrous + Stonecoil Serpent

Mortuary

Amareth, the Lustrous

Stonecoil Serpent

How it works

1. Cast Stonecoil Serpent by paying 0.
2. Stonecoil Serpent enters the battlefield and dies as a state-based action due to having zero toughness.
3. Mortuary and Amareth trigger.
4. Resolve the Mortuary trigger, putting Stonecoil Serpent on top of your library from your graveyard.
5. Resolve the Amareth trigger, causing you to reveal Stonecoil Serpent from the top of your library and put it into your hand.
6. Repeat.

By leveraging the zero mana value of Stonecoil Serpent, you can repeatedly cast it for free, only for state-based actions to immediately send it to the graveyard. This constant trip to the graveyard satisfies Mortuary, which dutifully places the serpent right back on top of your library. Meanwhile, Amareth, the Lustrous watches over the battlefield, eagerly triggering whenever the serpent re-enters; because Stonecoil Serpent is an artifact creature that matches its own type on top of your library, Amareth slides it directly into your hand, ready to be cast all over again in an endless loop.