Contested Cliffs

Onslaught block put removal where green and red had always been weakest: in the land slot, behind a tribal lock. Fight existed here long before the keyword had a name; this is the structural ancestor of every "creatures deal damage to each other" effect that later got cleaned up into Prey Upon and its kin. What sets this one apart is the gating. It demands a Beast you control as the aggressor, which turns it into a payoff for the dedicated Beast deck the set was building (Krosan Tusker, Ravenous Baloth, Wirewood Savage) rather than a generic removal piece anyone could splash. The repeatable, untap-and-go-again nature is the real engine: a single large Beast plus this land becomes a recurring fight machine that grinds an opponent's board down one creature per turn, all from a permanent that also taps for colorless mana when you have nothing to kill. The friction is doubled by the activation cost on a land that produces only , so the deck has to supply the colored mana elsewhere; the land is the trigger, not the fuel. It is fight-as-permanent rather than fight-as-spell, and that distinction (an answer that stays on the battlefield and asks no card from your hand each time) is why a tribally-restricted land could anchor a removal plan rather than merely supplement one.