Madame Web, Clairvoyant
Top-of-library card advantage engines usually gate the payoff behind a specific card type: Future Sight let you cast anything, Vizier of the Menagerie only creatures, Melek only instants and sorceries. This one carves out a hybrid lane, opening the top of your deck to Spider spells and to noncreature spells alike, which means the tribal shell and the spellslinger shell are both being fed from the same hidden card. The design tension is that the two halves compete for the same slot: every Spider you draw off the top is a noncreature spell you didn't, and the mill trigger on attack is what keeps the queue moving so the good half surfaces. That mill is doing quiet double work. It advances the top-card engine by one, and it self-mills value into a graveyard the color is well suited to reuse, so a card you couldn't cast from the top is not simply discarded but relocated to a zone blue and its allies can exploit. Persistent top-of-library visibility (permanent, not a one-shot scry) is the throughline: you are never guessing what the next mill will bury or what the next attack will unlock. The 4/4 body is incidental; the reason to run this is the information layer it bolts onto a deck that wants to know, and act on, what comes next.
