Mortuary + Bolas's Citadel + Phyrexian Marauder

Mortuary

Bolas's Citadel

Phyrexian Marauder

How it works

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

This clever loop uses Mortuary to instantly recycle whichever creature hits your graveyard right back to the top of your library. That positioning is vital because Bolas's Citadel allows you to play spells directly from the top of your library, swapping traditional mana payments for life. By casting Phyrexian Marauder for zero mana and zero life, it immediately enters the battlefield with zero toughness and dies as a state-based action, feeding the Mortuary trigger to start the cycle anew. This engine lets you continuously churn through your zero-cost artifact creature to rack up an arbitrarily large storm count or trigger any number of enters-the-battlefield and death effects.