Encrust

Pacification with a wider net. Where most blue removal-by-aura is content to lock down attackers and blockers, this one targets artifacts too, and it shuts off activated abilities on whatever it touches: no tapping a mana rock, no firing an artifact's marquee ability, no engine that runs on activations. The two clauses stack into a near-total deactivation. A creature it lands on won't untap and can't pump or sacrifice itself for value; an artifact it lands on becomes a brick that can neither contribute mana nor pull a lever. The no-untap line alone is the weaker half: an opponent left only tapped down is still free to crack a mana ability or pop a removal-on-a-stick, so the activated-ability lockout is the part doing the real cleanup against threats that don't mind being held still. The cost of that flexibility is the usual aura tax: it does nothing to a permanent that's already done its job, it dies with the enchanted thing, and it answers exactly one permanent at a time. It sits squarely in blue's school of soft removal: blue rarely destroys, it neutralizes, and this neutralizes with the dial turned up to cover the activated-ability problem that simple tap-down auras leave open.