Doc Ock's Tentacles

The equip cost is a bluff, and the design knows it. Five mana to move this onto a creature by hand is deliberately punishing, a rate no serious deck would pay for a +4/+4 anthem stapled to one body. The whole card lives in the trigger instead: land a creature of mana value five or greater and the Equipment snaps onto it for free, the moment it enters. That inversion is the tension the card resolves. Equipment normally taxes you twice, once to cast and once to reattach, which is what keeps a static buff this large in check. This one refuses to pay the reattachment tax as long as you keep feeding it fat creatures, so the constraint is not the mana but the deckbuilding: your curve has to top out high, and every heavy hitter you draw becomes a fresh attachment target that rebuilds the buff after the last one dies. Play a lean board and the thing is a dead one-drop with a five-mana albatross clause. Build around expensive creatures and it turns each of them into a threat two sizes larger the turn it arrives, no floating equip cost, no summoning-sick reattachment window. It is a big-mana payoff wearing the costume of an Equipment, and the free-attach trigger is the sleight of hand that lets a card this cheap carry a bonus this size.