Endurance

Free is the whole point. The Elemental Incarnation cycle it belongs to shares a template (a body with evoke, so you can pay full price for a creature or exile a same-color card for the effect at zero mana), but the reason this one reshaped how green plays defense is that its answer is graveyard hate that also flashes in as a 3/4 with reach. Green had never had an efficient, flash-speed way to shut off a graveyard combo mid-turn; the color's tools were slow, sorcery-speed, or off-color splashes. Evoking it by pitching a green card turns a live threat into a free instant-speed interrupt: point it at the reanimator player in response to the reanimation spell, scramble their yard to the bottom of the library, and lose only the pitched card and Endurance itself. It still gets cast as a spell and can be met by a counter, but a free-to-cast interaction rarely trades poorly. The self-scramble clause matters too, since bottoming your own graveyard can dodge mill or feed a shuffle in a pinch. What it fixes is green's chronic inability to say no; here the color says no for free, at instant speed, while still leaving a hard-to-kill blocker on the battlefield if you paid the mana instead. That dual identity, disposable answer or permanent body, is what makes it a fixture wherever green touches an interactive shell.