Sphinx of Uthuun

Fact or Fiction stapled to a 5/6 flier is the whole pitch, and the upgrade over the spell is quietly meaningful. The instant resolves and is gone, a one-time exchange of mana for cards; here the same split happens as a 5/6 flying threat lands, so even the pile that goes to the graveyard comes attached to a clock rather than a single draw step. The forced division is the cost the design pays for digging five deep: an opponent who knows your deck will always hand you the worse half, splitting three-two against your best cards and two-three against your bombs, which makes the reveal as much a read on your library's quality as a raw card-advantage engine. In a graveyard-agnostic deck the floor is still better than most seven-mana payoffs, since the pile in the graveyard is surplus you were never going to cast anyway. The number that does the heavy lifting is the toughness: 6 survives most sweepers' damage thresholds and the bulk of single-target burn, so the value isn't a one-and-done trigger, it's bolted to a body that lingers and demands an answer of its own. This is the fair, top-heavy value creature built for grindy blue mirrors, where the flier matters as much as the cards drawn and an opponent's most miserly split still leaves you ahead on board and material both.