Barbed Bloodletter

The flash-and-attach clause is doing something quietly aggressive: because the Equipment enters and jumps onto a creature at instant speed, granting wither until end of turn, this is really a combat trick wearing an Equipment's clothes. Hold up mana, wait for a block, then flash it in to turn ordinary combat damage into permanent -1/-1 counters, shrinking whatever your creature hits for good rather than just for the turn. The +1/+2 buff sweetens the ambush, but the wither window is where the card earns its keep, and that window closes at end of turn: after this first attach, the equip cost of only ever buys you the stat line, not the wither. The design is front-loaded on purpose. The one-shot wither rewards deploying it in the right combat step rather than treating it as a permanent Equipment you shuffle between attackers turn after turn. It collapses two normally separate cards, a pump spell and a persistent Equipment, into one artifact that can be held for the surprise and then left behind to keep its wearer bigger. The catch is that you pay full price up front and get the trick only once: the wither is a single-use rider on an Equipment that stays behind as a modest stat boost, so the price of the ambush is that the ambush never comes again.