Ulalek, Fused Atrocity + Lithoform Engine + Kozilek's Unsealing

Ulalek, Fused Atrocity

Lithoform Engine

Kozilek's Unsealing

How it works

1. Cast an Eldrazi from your hand by paying its mana cost.
2. Ulalek triggers, the Eldrazi cast triggers if it has a cast ability, and Kozilek's Unsealing's first ability triggers.
3. Holding priority, activate Lithoform Engine's first ability by paying 2 and tapping it, copying Ulalek's trigger.
4. Resolve the copy of Ulalek's trigger, causing you to pay CC to copy the Eldrazi spell, Ulalek's trigger, the Eldrazi cast trigger if it had one, and the Kozilek's Unsealing trigger.
5. Resolve the Eldrazi cast trigger, if applicable.
6. Resolve the copy of the Kozilek's Unsealing trigger, creating two 0/1 Eldrazi Spawn creature tokens.
7. Activate both Eldrazi Spawn creature tokens by sacrificing it, adding CC.
8. Resolve the copy of Ulalek's trigger from step 4, causing you to pay CC to copy the Eldrazi spell, Ulalek's trigger, the Eldrazi cast trigger if it had one, and the Kozilek's Unsealing trigger.
9. Repeat from step 5.

This marvelous loop begins the moment you cast an Eldrazi creature with a mana value of 4, 5, or 6, immediately triggering both Ulalek, Fused Atrocity and Kozilek's Unsealing. By using Lithoform Engine to kickstart an initial copy of Ulalek's triggered ability, you enter a magnificent cascade where paying colorless mana creates fresh copies of your original spell, the enchantment's token generation, and the copying engine itself. The Eldrazi Spawn tokens provided by Kozilek's Unsealing can then be sacrificed right back into the mana pool to continuously pay for Ulalek, Fused Atrocity's stacking costs, letting you snowball an unstoppable avalanche of infinite copies and triggers.