Koskun Falls

A defensive tax dressed as an enchantment, built on a tension that almost no card from its era bothered with: it makes you spend resources every turn just to keep it on the table. The upkeep clause demands an untapped creature each turn or the whole thing goes to the graveyard, which means the card you most want to protect your life total also costs you a blocker (or an attacker, or a mana dork) every single turn it stays alive. That self-imposed friction is the design discipline that justifies the rest: a creature-by-creature attack tax steep enough to wall an aggressive board, but only for as long as you can feed it. The World designation adds a second pressure valve, since two of these cannot coexist; the newer one replaces the older. The whole package reads as a study in how to price a near-unconditional defensive lock so it doesn't simply end the game. Pillow-fort effects that followed mostly chose a one-time cost or a static tax with no upkeep; Koskun Falls instead asks for a recurring tithe, and the question of whether you can keep paying it is the entire game it creates. It is the rare card whose drawback is doing more interesting work than its headline ability.