Pentavus + Cauldron of Souls + Clock of Omens + Krark-Clan Ironworks

Pentavus

Cauldron of Souls

Clock of Omens

Krark-Clan Ironworks

How it works

1. Activate Cauldron of Souls by tapping it, giving Pentavus persist until end of turn.
2. Activate Krark-Clan Ironworks by sacrificing Pentavus, adding CC.
3. When Pentavus dies, its persist ability triggers, returning it from your graveyard to the battlefield with four +1/+1 counters on it.
4. Activate Pentavus' first ability twice by paying 2 and removing two +1/+1 counters from it, creating two 1/1 Pentavite artifact creature tokens.
5. Activate Clock of Omens by tapping Pentavus and a Pentavite, untapping Cauldron of Souls.
6. Repeat.
7. Once you have infinite colorless mana and Pentavite tokens, you may use Pentavus' second ability to put infinite +1/+1 counters on it.

This intricate loop is a masterclass in recycling through the graveyard, centered around Pentavus and the persistent protection granted by Cauldron of Souls. When Krark-Clan Ironworks feeds on Pentavus for raw colorless mana, the persist trigger brings it right back with a fresh lease on life, while Clock of Omens uses the resulting Pentavite tokens to continually untap the Cauldron and keep the cycle going. By stripping away counters to build tokens and then sacrificing them for fuel, you generate boundless mana, death triggers, and infinite counters to overwhelm the battlefield.