Black Cat, Cunning Thief
Theft-of-cards effects usually pay for themselves in inefficiency: you dig, you exile, and then you sit on cards you may never have the mana to cast. The last clause settles the second half of that bargain, letting any type of mana pay for the exiled spells. That turns a mono-black creature into a legal caster of whatever it steals, which is where the design gets pointed: the deeper the opponent's mana requirements, the more the theft actually costs them, because the color-fixing lives on the effect rather than in your deck. The look-at-nine, exile-two shape is a wide dig for a narrow haul, more surgical strike than grinding engine; you get first pick of the top of a library and leave the rest scrambled. Note what the ability withholds as much as what it grants: the exiled cards stay yours for as long as they remain exiled, so removing the 2/3 body does nothing to return them, and there is no clock ticking down the way impulse-draw effects expire at end of turn. The frame is beside the point. This is a five-mana card that hands you a lasting claim on two of an opponent's best cards and the means to cast them, all stapled to a modest Rogue.
