Morkrut Necropod

A 7/7 with menace for six is a rate any black deck would take in a vacuum; the catch is that this slug eats your board to swing. The attack-or-block trigger is mandatory, so every combat step it participates in costs you a permanent, and the choice of what to feed it (another creature or a land) is yours. That freedom is exactly what makes the card a liability left unattended: with no expendable bodies around, it happily starts strip-mining your own mana base to keep swinging. The design idea here is the self-sacrifice drawback as a deckbuilding prompt rather than a downside to endure. Feed it tokens, feed it creatures that want to die, feed it permanents with leave-the-battlefield triggers, and the mandatory sacrifice flips from tax to engine. Left alone, it is a beater that slowly disassembles its controller's position. Surrounded by the right fodder, it is a recurring sacrifice outlet that also happens to punch for seven and demand two blockers. Because the trigger fires on blocking too, it cannot sit back as a passive wall without paying the same toll: there is no free defensive anchor here, only a body that taxes you in every combat it enters. It belongs to the lineage of huge-body-real-cost black fatties that ask you to build around the leash instead of pretending it isn't there.