Shivan Gorge

Most damage engines that live on a land charge a tax in tension: a self-inflicted wound, a steep upkeep, a fragile body that folds to a stray Disenchant. This one asks nothing of the deck around it. It taps for colorless when you need a land and converts surplus mana into a point of damage when you don't, and because the clock sits on a permanent that reads as a land, it survives the wraths, counterspells, and sweepers that switch off every other source of inevitability in a grinding control game. The activation locks up four mana in total ( from elsewhere plus the Gorge's own tap), which is what holds it short of a real win condition in the mold of Cursed Scroll: this is a slow leak, not a faucet. But a slow leak is exactly what a low-resource, attrition-bound game wants, a recurring damage source that costs no card to deploy and never has to be recast. The "each opponent" clause is where it earns its keep at a crowded table, multiplying its output by the number of players without ever raising the price of the activation. It is built for the deck that plans to go long, has nothing better to do with its mana in the late turns, and is content to win by turning every stalled game state into a steadily mounting loss for everyone else.