Tombstalker

Delve was the keyword that turned the graveyard from a resource you protected into a currency you spent, and this Demon was its proof of concept. The printed cost reads as eight mana, the kind of number reserved for game-ending haymakers, but the body it buys is a plain 5/5 flier. The trick is that you almost never pay full freight: a graveyard stocked with spent removal, fetched lands, and dead creatures becomes generic mana, collapsing the cost down to two black and a fistful of exiled cards. That inversion is the whole design. A card normally read as a payoff for surviving to the late game instead arrives early in any deck that fills its own yard, and it punishes opponents who let cards pile up unanswered. The tension built into delve is that you are racing your own graveyard against your other uses for it: every card the Demon eats is one your flashback, your threshold, your delve removal cannot. It rewards a deck that overflows the graveyard faster than it can drain it, and every cast becomes a referendum on whether a 5/5 flier now is worth the resources you are setting on fire to get it. Delve has since been refined into tighter, cheaper packages, but this was the clean statement of the idea: a fixed cost on paper, a sliding cost in practice, paid in the cards behind you.