Advent of the Wurm

A 5/5 trampler for four mana is an honest body; printing it on an instant is the whole design. Green-white midrange would rather not tap out on its own turn, and this lets it hold up mana, wait for the opponent to commit to a sweeper or a removal spell or an attack, then drop a five-power clock in the window they have already passed. The Wurm arrives like a combat ambush or an end-step deployment: a finisher-sized creature delivered on a window normally reserved for tricks. Because the card is an instant rather than a creature spell, it slips past the narrow band of counters that only answer creatures on the stack, things like Essence Scatter, which see nothing here to grab. The token framing is the quieter half. There is no enters-the-battlefield trigger, no upkeep tax, no sacrifice clause to pay for the size, so the cost lives in the indirection: you get a token, not a permanent card, so once the Wurm dies there is nothing to recur, recast, or grind with, and trample is what keeps it from being a mere surprise blocker. A 5/5 that only ambushes taxes the opponent's combat math; one that runs over chump blocks ends the game. Everything that matters lives in the timing and the token, not in any line the card leaves on the battlefield.