Shoving Match

What the card grants is symmetric, and that symmetry is exactly what kept the effect from spreading: it hands every creature on the battlefield, yours and your opponent's alike, a tap-down at instant speed. The name spells out the intent. This was built for a combat-math era where denying a blocker or pre-tapping an attacker was a real tempo lever, and where arming the other side's board too turned the card into a political object rather than a clean answer. The timing is tighter than the line first reads. A granted ": Tap target creature" only works on untapped creatures, and declaring attackers is a turn-based action that resolves before anyone gets priority, so you cannot pull a creature out of an attack it has already committed to (a vigilant attacker stays in combat even after being tapped). To stop a creature from swinging, you have to act in the beginning-of-combat step, before declare-attackers ever arrives; to stop one from blocking, you can wait until after attackers are declared: tap it down and it can neither attack this turn nor be declared as a blocker later. You spend whatever untapped bodies you already control rather than the card itself on a single target. Blue's removal has always been oblique, and this is removal-by-denial: it kills nothing, it just lifts a creature out of the turn's combat. The symmetric grant is the cost of the flexibility, and it was a cost most decks declined to pay, which is why the effect stayed a one-off rather than founding a lineage.