Sibling Rivalry

Threaten effects have always paid for themselves in tempo: steal the blocker, swing for the whole board, hand the borrowed body back at cleanup with nothing to show for it. This one rewrites the ledger. The Powerstone token stays behind after the annexed permanent goes home, converting a one-turn tempo swing into a permanent mana rock (a restricted one, spendable only on artifacts, but a rock nonetheless). That leftover token is the whole difference from the usual read-and-discard theft spell: whatever you point it at, you walk away with a colorless ramp piece attached to a haste enabler. The wider target line matters too. Most creature-theft spells stop at creatures; opening the clause to artifacts means you can annex a Signet, an opposing engine piece, or a mana rock for a turn, untap it to squeeze value before the swing, or feed it to your own sacrifice outlets. Note the constraint that keeps the spell honest: it requires a target artifact or creature rather than "up to one," so it cannot be cast against a genuinely empty battlefield. That is the price for the ramp bolted onto the borrow. When there is any legal target, though, the transaction is net-positive no matter what you steal, a very different profile than the threaten effect whose entire value evaporates the moment the opponent has nothing worth taking.