Mikaeus, the Unhallowed + Cryptic Trilobite + Engineered Plague

Mikaeus, the Unhallowed

Cryptic Trilobite

Engineered Plague

How it works

1. Activate Cryptic Trilobite by removing a +1/+1 counter from it, adding CC that can only be spent to activate abilities.
2. Repeat step 1 until Cryptic Trilobite does not have any +1/+1 counters on it.
3. Cryptic Trilobite dies as a state-based action due to having 0 toughness.
4. Cryptic Trilobite's undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
5. Repeat.

This ingenious loop turns a fragile insect into a self-sustaining mana engine by exploiting the interaction between static buffs and death mechanics. When you cast Engineered Plague naming Trilobite's creature type, it shrinks Cryptic Trilobite so that its base toughness becomes zero, meaning it will immediately perish whenever it lacks +1/+1 counters. Meanwhile, Mikaeus, the Unhallowed provides the crucial static anthem and undying safety net that lets Cryptic Trilobite return to the battlefield every time it succumbs to that state-based check. By stripping away its counters for mana and letting it continuously die and resurrect, you generate infinite colorless mana restricted to abilities along with an endless stream of entry and death triggers.