Gloom Stalker

Double strike on a 2/3 for three mana is a real payoff, and the venture-into-the-dungeon mechanic was built precisely so a card like this could sit at common-adjacent power without breaking anything. The ability is a switch, not a scaling reward: once you have completed a single dungeon, the body permanently threatens four damage a swing and starts eating combat trades it would otherwise lose. Before that flip, it is a fair 2/3 blocker, which is the honest tax the design charges. What makes the switch elegant is that venture front-loads its own cost onto other cards in your deck: the dungeons themselves generate value on the way to the finish line, so the completion requirement is rarely a hoop you jump through only to turn this dwarf on. It comes free with the incidental progress a venture deck was going to make anyway. That is the quiet efficiency of a binary-payoff design: the card asks nothing of its own slot to earn the upgrade, deferring the whole cost to the deck's engine. It rewards commitment to a subtheme rather than building around itself, so it plays as a modest role-player until the surrounding deck is assembled, at which point a three-mana creature quietly starts trading up the curve.