Martial Law
Most disabling enchantments commit to a single body and never let go: Pacifism, Arrest, and Faith's Fetters each pin one creature for as long as they stay on the battlefield. This one works the opposite way. It binds nothing permanently, instead choosing a fresh victim on each of your upkeeps, so the shackle migrates to whatever has become the most dangerous thing on the other side of the table. That makes it a soft removal spell that never actually removes anything: the targeted creature stays alive, technically present, but can't attack, block, or activate its abilities for a full rotation, and next turn the trigger can pick someone else entirely. Its ceiling is set by the single-target restriction. It only ever neutralizes one creature, and only one your opponent controls, so a developed board strolls past it and a new threat each turn outruns the lone upkeep trigger. Point it at a deck leaning on one expensive finisher or a key mana creature, though, and it becomes a recurring tax the opponent can't pay off without diversifying the board. The keyword it carries was designed to make tempo behave like attrition, handing the controlling player a turn of safety per use; anchoring that one-shot effect to a permanent's upkeep turns a single beat of breathing room into an indefinite one, a controlling white piece that wins by keeping the opponent's best asset asleep indefinitely.
