Chant of the Skifsang

Power reduction is one of blue's oldest pacifism tricks, and this is the variant that solves the problem by overcorrection: drop the enchanted creature's power by thirteen and almost any attacker on the board becomes a 0/X wall, swinging for nothing. The toughness left untouched is the tell. This is not removal; the creature survives, blocks, and keeps whatever defensive value it had, so the Aura neutralizes a threat's offense without granting the controller the satisfaction of a kill or the card to bury it. That makes it a strict combat-and-attrition tool rather than an answer, and it carries the usual liabilities of any single-target Aura: it goes to the graveyard if the creature leaves, and it is dead weight against a board you cannot afford to merely defang. The -13 is chosen to be functionally absolute against ordinary creatures while still being a real number, which matters in the rare cases where a creature's power is being pumped past it or where some other effect cares about the actual figure. Compared with a clean Pacifism-style "can't attack or block" lockdown, this leaves the creature able to block, an asymmetry that occasionally cuts against you when the opponent simply parks their neutered monster in front of your attackers.