Myr Welder + Encroaching Mycosynth + Empowered Autogenerator + Merrow Grimeblotter

Myr Welder

Encroaching Mycosynth

Empowered Autogenerator

Merrow Grimeblotter

How it works

1. Activate Myr Welder using Empowered Autogenerator's ability by tapping it, putting a charge counter on Myr Welder and adding or for each charge counter on Myr Welder.
2. Activate Myr Welder using Merrow Grimeblotter's ability by paying 1U/B and untapping it, giving target creature -2/-0 until end of turn.
3. Repeat.

This loop brilliantly transforms Myr Welder into a self-sustaining engine by utilizing Encroaching Mycosynth to treat all permanent cards as artifacts in any zone, allowing Myr Welder to effortlessly feast on Empowered Autogenerator and Merrow Grimeblotter from the graveyard. Once those cards are exiled into Myr Welder's imprint, the creature gains both the mana-producing, counter-accumulating ability and the untap ability required to fuel an endless cycle. By tapping to generate escalating amounts of mana and charge counters—and paying a fraction of that mana to untap via Merrow Grimeblotter—you can repeat the process infinitely to generate unbounded colored mana and limitless charge counters.