Gloomdrifter

Threshold did its most honest work on cards like this: a body that is fine on its own and frightening once the graveyard fills, with the cost paid in the patience it takes to get there. Empty the seven-card requirement and you have a 2/2 flyer, a clock and nothing more. Hit threshold and the enters trigger turns it into a one-sided sweeper-on-a-stick, wiping nonblack X/2s and shrinking everything else, while your own black creatures walk through untouched. The asymmetry is the point: in a Torment-era black deck the board state after this lands is yours and yours alone. What makes the timing notable is that the -2/-2 fires on entry rather than as a static effect, so it is a single burst rather than a persistent anthem against the opponent; it punishes the board as it exists the moment you commit, not the board they rebuild afterward. That entry trigger also means recursion (returning Gloomdrifter to hand or graveyard and replaying it) reloads the sweep, which is where the card stops being a curve-filler and starts being an engine. The threshold clause is the gate that keeps a four-mana 2/2 from also being free removal: you have to spend a game getting your graveyard deep before the card pays out, and a deck built to do that is a deck built around the whole threshold mechanic, not around this one creature.