This opponent's whole plan runs through colorless permanents and lands like Eldrazi Temple, Ugin's Labyrinth, and Urza's Saga, making Meltdown a two-for-one against their manabase and artifacts while dodging their removal suite. Blood Moon is devastating since almost their entire mana base is nonbasic and colorless-producing. Obsidian Charmaw comes down cheap off their colorless lands and blows up a key nonbasic land while adding a flying clock. Spell Snare and Spell Pierce are weak since most of their key spells (Emrakul, Devourer of Destiny, Kozilek's Command at higher X) dodge those mana values, so they come out for the more proactive hate pieces.