Portent of Calamity

The reward for going wide is a lesson in card-type diversity that most blue spells never bother teaching. The X cards you reveal don't all become gas: you keep only one of each card type, so the payoff scales not with how much you dig but with how many kinds of things you find. A pile of six creatures nets you exactly one creature and dumps the rest into the graveyard; a spread of a creature, an instant, a sorcery, an enchantment, and a land turns the whole reveal into value plus a free spell. That four-or-more threshold to cast something without paying its cost is the payoff clause, and it quietly rewrites how you build around the spell: not toward raw card advantage but toward a spread of types, with artifacts and enchantments and the odd planeswalker earning slots they wouldn't otherwise get. The graveyard filling is not incidental either, since everything you can't keep goes there rather than back into your deck, feeding whatever wants a stocked yard. The deckbuilding question it poses is genuinely unusual, concerned with the shape of your library rather than its power level, and the answer stays useful from cheap early-game filtering all the way up to a game-ending X.