Six mana for half an opponent's library at instant speed is a sideboard curiosity nobody wants to cast. Two mana to cash in a connected attacker for that same mill is the only version that matters, and the math determines exactly when it matters: never early. Against a fresh forty-card library, milling half rounded up takes twenty cards and leaves twenty. Cast it again and you halve what remains: ten, then five, then three. The yield shrinks every time, so this is a closer that only converts once attrition has already gutted the deck. Against an opponent sitting on eight or ten cards, one Sneak cast is lethal pressure. From a full library it is a tempo concession that happens to chip away, and a real one, because the Sneak cost requires bouncing your own unblocked attacker before damage. You give up the board presence and the swing you committed to in exchange for a discount. That is a price, not a trick.
UR Sneak is the only home, with GU as a secondary seat that fields evasive bodies to carry the connect. Pick band is P1P5 to P1P7 in a blue seat that already owns a flier or a menace body; outside blue it is unpickable. The connect is policed every game in a medium-speed format with one or two removal commons per color. Stomped by the Foot kills the carrier before you declare; Grounded for Life punishes the tapped attacker on the swing-back. And the bounce returns only the creature: lean on an equipped attacker to force damage through and you strand Bespoke Bō on the battlefield the moment you cash in.

