Karn's Touch

Naming the spell after Karn, the silver golem who could not touch organic life and wandered Magic's story half-alive, is the rare case of flavor and function landing on the same idea: this turns inert metal into something that can fight. The mechanic is a one-turn animation that scales off mana value, so the giant artifacts (the ones costly enough to justify the spell) come out swinging hardest, while a humble trinket becomes a 0/0 and falls over. That floor is what governs the card: it cannot grant evasion, cannot grant haste, and a zero-cost object (a Treasure, say) animates into nothing, so the spell wants an artifact already on the battlefield and expensive enough to absorb a turn of exposure as a creature. The instant-speed window is where the angle lives. Animating your own mana rock to block a swing, or pointing the spell at an opponent's artifact so it becomes a creature and then dies to a sweeper or to removal that only hits creatures, are both live lines, and the second quietly turns a defensive instant into part of an answer suite. It is a narrow tool dressed as a combat trick, built in an era when artifacts were rarer and clunkier than they are now, which is part of why the rate reads generous: it needs a big artifact worth animating to do much at all.