Requires

Ulalek, Fused Atrocity must be on the battlefield. Strionic Resonator must be on the battlefield. Kozilek's Unsealing must be on the battlefield. Mana needed: plus enough mana to pay for the Eldrazi spell

Steps

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 Strionic Resonator by paying and tapping it, copying Ulalek's trigger.
4. Resolve the copy of Ulalek's trigger, causing you to pay 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 .
8. Resolve the copy of Ulalek's trigger from step 4, causing you to pay 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.

Results