Mortuary + Ranger Class + Cryptic Trilobite

Mortuary

Ranger Class

Cryptic Trilobite

How it works

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

This clever loop centers around Cryptic Trilobite entering the battlefield with zero toughness (when cast for zero mana) and immediately heading to the graveyard as a state-based action, which triggers Mortuary to seamlessly recycle it right back to the top of your library. From there, Ranger Class acts as the crucial engine piece, allowing you to continually cast that same creature straight off the top of your library to repeat the process indefinitely.