Flatline

A one-sided board wipe that leaves the board intact. Instead of destroying creatures, it strips every opponent's creature down to a 0/1 base, which is a very different lever: it turns off attackers and blockers alike, nullifies power-scaling abilities and combat-relevant toughness, and does it all at instant speed without touching a single permanent on your side. The non-destructive framing is the whole trick. Because the change is base power and toughness rather than a static minus, buffs and counters still layer on top, but the raw bodies underneath are neutralized, and any creature already sitting at exactly one damage or a lethal minus dies to state-based checks the instant its toughness collapses. The instant timing separates this from a symmetric Fog. Cast in response to a declared attack and the swing evaporates; cast before combat on your own turn and every blocker becomes a chump that dies to a 1/1. It shares a lineage with the old Humble line and the temporary-shrink effects blue and white have long used to blunt aggression, but pushing the effect to the entire opposing board, in blue, at sorcery-proof speed, is the aggressive version of that idea. The catch is the "until end of turn" clause: this buys a turn, not a game, so it wants to punctuate a race or set up an alpha strike rather than stall indefinitely.