Serum Sovereign

Two abilities pulling in opposite directions is the puzzle at the center of this Sphinx. It stockpiles fuel passively, banking an oil counter every time you cast a noncreature spell, but the payoff is gated behind an activated ability rather than a triggered one, and that distinction is the entire engine. Because you choose when to cash in, you can hold the reserve across turns and fire the draw-plus-scry-2 on an opponent's end step or in response to removal that would otherwise strand the value. What complicates the loop is that the counters live and die with the body: no death trigger, no way to move them, no way to activate without the creature on the battlefield. Feed it and protect it and you have a repeatable card-selection engine that also flies over for four; miss on either count and you have paid five mana for a flier that never drew a card. The awkward part is that the two demands want different lists. A shell dense with counterspells, cantrips, and cheap card advantage fills the reserve far faster than any creature-heavy deck could, yet that same shell fields the fewest bodies to keep a 4/4 flier alive while an opponent points removal at it before it accumulates anything worth spending. The card asks for high noncreature-spell density and durable board presence at once, a combination that rarely coexists cleanly, which is what makes it a build-around rather than a slot-in.