Derelor

A 4/4 for four mana in black was a genuinely good rate in this card's era: the body alone would have justified the slot. The static cost is what turns it into a riddle. Taxing every black spell you cast by an extra is a self-inflicted symmetry, a downside that scales with how committed you are to your own color. The harder you lean into black, the more the tax bites, which inverts the usual relationship between a creature and the deck it lives in: most beaters get better in a dedicated shell, this one gets worse. The design tension here is between rate and identity. Pay full mono-black devotion and the thing actively works against your curve; splash it in a shell that casts few black spells and you keep the body while shrugging off the tax, but then you are paying for a Thrull's flavor in a deck that does not want it. It belongs to a brief school of design when Wizards still priced aggressive bodies behind genuinely punishing static costs rather than once-and-done downsides, drawbacks that compounded with your every subsequent play rather than resolving in a single moment. As a piece of black's history it documents a moment when "undercosted" came with a string attached you could never cut.