A-Ominous Parcel

Two objects live inside one artifact, and it commits to neither until you spend it. Pay one generic mana, tap, and sacrifice it to fetch a basic land straight to hand: frictionless fixing that trades the object for a resource you actually need, ending at card parity rather than card advantage. Wait, and the same artifact becomes a slow removal spell, sacrificing itself to deal 4 damage to a creature when the game runs long. The finality is the whole balancing lever: every activation, either mode, sends the artifact to the graveyard, so you pick one job and pay for it once. What survives is the split personality that made the object worth printing in the first place: mana when you are short on lands, an answer when you are flooded, and an artifact that chooses between the two by consuming itself.