Mairsil, the Pretender + Blood Vassal + Endling + Cryptic Trilobite

Mairsil, the Pretender

Blood Vassal

Endling

Cryptic Trilobite

How it works

1. Activate Mairsil using Endling's third ability by paying , giving Mairsil undying until end of turn.
2. Activate Mairsil using Blood Vassal's ability by sacrificing it, adding .
3. Mairsil dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
4. Activate Mairsil using Cryptic Trilobite's first ability by removing a +1/+1 counter from it, adding CC that can only be spent to activate abilities.
5. Repeat.

This ingenious loop turns Mairsil, the Pretender into a one-commander engine by cage-caging the right pieces from your hand or graveyard. By exiling Endling, Mairsil gains the vital undying ability that allows it to return to the battlefield whenever it dies, while Blood Vassal provides the sacrifice outlet needed to trigger that death and refund your investment with black mana. Meanwhile, Cryptic Trilobite supplies the crucial +1/+1 counters—which Mairsil accumulates upon returning via undying—that can be stripped away to fuel further activations. Together, these caged abilities create a self-sustaining loop that generates infinite mana and unlimited triggers.