Worldspine Wurm

The mythic at the top of green's curve, and the rare giant that refuses to stay dead. Eleven mana buys a 15/15 trampler, but the design problem with a creature this expensive is what happens when it dies for free: a Doom Blade or an edict erases the whole investment. The card answers that twice. The death trigger replaces one 15/15 with three 5/5 tramplers, so even spot removal leaves fifteen power on the board across three bodies. The second clause, which fires whenever the Wurm hits a graveyard from anywhere (the battlefield, the library, the hand), shuffles it back into the deck instead of letting it linger. That is the more unusual piece of design, and the reason it reaches past death: it treats the graveyard as a temporary stop and the library as the Wurm's true home, recycling the threat into future draws rather than leaving it as a Reanimate target. The combined effect is a finisher that punishes spot removal, denies cheap shortcuts (you cannot mill it and cheat it back, and graveyard hate finds nothing to chew on), and keeps recurring as long as the game runs long, which is the inevitability a top-end green creature is built to provide. The cost keeps it honest: at eleven mana, getting it onto the battlefield the fair way is its own deckbuilding project, and the shuffle clause makes the unfair ways meaningfully harder.