Mask of the Jadecrafter

Two mana buys a placeholder, not a threat: the artifact sits there doing nothing until you have the mana to convert it, and the conversion is a full sorcery-speed activation that eats your turn. What justifies the wait is the elasticity of the payoff. The X/X Golem scales with every extra land, so the same card that makes a 3/3 in the early turns makes a game-ending body in the late ones, and the sacrifice clause means the artifact you were holding is spent to build the creature rather than left as a target. The unearth mode is the wrinkle that separates it from a plain mana sink. Because unearth returns the card to the battlefield, not the hand, and exiles it at end of turn, the Golem factory comes back for a single decisive activation before it leaves for good: a graveyard-based second use that reads less like recursion and more like a scheduled encore. The green cost on that ability is the only color commitment the card asks for, which lets the artifact half slot into any deck while the payoff stays gated behind green mana. It is a mana sink built for the long game, priced cheaply up front so the artifact is never a dead draw and always a promise of a bigger creature later.