Phyrexian Altar + Lesser Masticore + Hardened Academic

Phyrexian Altar

Lesser Masticore

Hardened Academic

How it works

1. Activate Phyrexian Altar by sacrificing Lesser Masticore.
2. When Lesser Masticore dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Hardened Academic triggers, putting a +1/+1 counter on Lesser Masticore.
4. Repeat.

This loop turns the cycling of a single mechanical bug into a perpetual engine by using Hardened Academic as a brilliant counterweight to persist; whenever Lesser Masticore dies and returns with a -1/-1 counter, the Academic's graveyard trigger steps in to place a +1/+1 counter that immediately cancels it out. Because Lesser Masticore is continuously fed to Phyrexian Altar along the way, this mutual annihilation of counters leaves the creature entirely clean of debuffs every single time it loops. The result is an inexhaustible stream of sacrifice, death, and entry triggers that funds an infinite supply of colored mana.