Ulalek, Fused Atrocity + Echoes of Eternity + Kozilek's Unsealing

Ulalek, Fused Atrocity

Echoes of Eternity

Kozilek's Unsealing

How it works

1. Cast an Eldrazi with mana value 4, 5 or 6 from your hand by paying its mana cost.
2. Ulalek and Kozilek's Unsealing's first ability trigger twice, the Eldrazi cast triggers twice if it has a cast ability, Echoes of Eternity triggers once if the Eldrazi cast was colorless.
3. Resolve the first Ulalek's trigger, causing you to pay CC to copy the Eldrazi spell, the additional Ulalek's trigger, both Kozilek's Unsealing triggers, both Eldrazi cast triggers if it had one, and the Echoes of Eternity trigger if it triggered.
4. Resolve both Eldrazi cast triggers, if applicable.
5. Resolve both Kozilek's Unsealing triggers, creating four 0/1 Eldrazi Spawn creature tokens.
6. Holding priority, activate two Eldrazi Spawns by sacrificing them, adding CC.
7. Resolve the copy of Ulalek's trigger from step 3, causing you to pay CC to copy the Eldrazi spell, the additional Ulalek's trigger, both Kozilek's Unsealing triggers and any other abilities on the stack.
8. Repeat from step 4.

This fascinating loop turns a single mid-sized Eldrazi cast into an unstoppable avalanche of colorless power. As you cast your creature, Echoes of Eternity copies the spell while doubling your triggers, and Kozilek's Unsealing steps in to provide the crucial Eldrazi Spawn tokens needed to feed the engine. With those tokens ready to sacrifice for mana, Ulalek, Fused Atrocity acts as the ultimate multiplier: by paying {C}{C} to copy everything on the stack—including Ulalek's own trigger—you perpetuate an infinite feedback loop that floods the board with infinite copies, tokens, and resources.