Charmed Sleep

The lineage of blue's Pacifism variants is a long argument about which half of a creature to shut off, and this one leans on the tap rather than a behavioral clause. Where Pacifism actually forbids attacking and blocking, this Aura works mechanically: it turns the creature sideways the instant it resolves, then denies the untap step that would straighten it back up. The result covers both axes as long as no one intervenes. A tapped creature cannot attack and cannot be declared as a blocker, so the body sits inert until the enchantment leaves. That last qualifier is the whole seam in the lock. Because the shutdown is nothing but a tap that never reverses on its own, any outside untap effect (a Vitalize, an untapper, anything that straightens a creature off-schedule) frees the body to attack or block while the Aura is still attached. It is a functional cousin of earlier three-mana blue tappers like Claustrophobia, so the design conversation is really about the archetype rather than the individual card. The tap-on-entry also makes it tempo as much as answer: you strip a blocker and swing in the same turn. The liabilities are the liabilities of every Aura: it is two-for-one bait for bounce or blink, it does nothing against a creature that wants to be tapped, and it leaves the body alive to be sacrificed or reanimated. What it buys is a clean, near-permanent lock at a fair rate, the compromise blue accepts when it wants a threat off the table without killing it.