Engineered Explosives should be cast for X=0 so it enters with no charge counters. Chalice of the Void has mana value 0 on the battlefield whatever its charge counters, so activating Explosives with 0 counters destroys it. That matters because Chalice can lock our deck out of casting cheap spells. The same activation also destroys any Lotus Petal and any Eldrazi Spawn or Scion tokens. Consign to Memory counters colorless spells, hitting their Eldrazi threats like Reality Smasher, Thought-Knot Seer, Glaring Fleshraker, and It That Heralds the End, all of which are colorless. It can also counter a triggered ability, such as Thought-Knot Seer's enter trigger or Eldrazi Linebreaker's beginning-of-combat trigger. That covers most of what Stifle would hit, so Stifle comes out. Ponder is trimmed slightly since we want more interaction and less card selection against a fast clock.