Winding Wurm

A 6/6 for five mana looks like a steal until you read the upkeep clause, and then the deal reveals itself: you are buying the wurm on installment, paying once to put it down a turn ahead of curve, then settling the balance to keep it. Miss that second payment and the body walks, which is the trade laid bare with nothing to soften it. There is no death trigger, no enters-the-battlefield bonus, no parting gift if you let it slide. It is pure size traded for a deferred bill, and the only decision the card asks is whether the rest of your turn can shoulder the cost when it comes due. That bareness is what makes it instructive: no consolation prize muddies the math, so the layaway logic of the keyword sits in plain view. Echo as a mechanic largely faded after the block that introduced it, supplanted over the years by flicker and recursion effects that hand you a creature without the recurring tax attached. This one is the idea stripped to its frame, a flat green beater that poses the question (settle up or lose it) without any dressing to distract from the answer.