Starlight Snare
Blue's removal has always been oblique: it does not kill creatures, it embarrasses them. This is the freezing school, descended from the Icy Manipulator lineage that pins a permanent down and refuses to let it wake up, distilled into a single Aura that arrives, taps its target, and cancels its untap step until the enchantment is pried loose. A raw tap effect hands the creature back next turn; this converts a one-time swing into a standing lock. The tapped-on-entry clause makes it proactive as much as defensive: enchant an untapped potential attacker or blocker and the body is simply switched off. The permanence is paid for in softness. The target never leaves play, so it still counts as sacrifice fodder, still triggers whatever cares about board presence, and any way to peel the Aura off lets the creature untap again on its next turn. That same softness cuts the other way against indestructible threats, where freezing is often the cleanest answer available: you cannot destroy the thing, but you can leave it tapped indefinitely and play around a body that never swings. It is a fair answer, not a hard one, the kind blue is allowed to have precisely because it leaves a door open.

