Ice Cage

The blue answer to the old Pacifism problem: how do you neutralize a creature with an Aura when blue isn't supposed to get clean, permanent shutdowns? The fix is a built-in expiration clause. The enchanted creature is fully locked down (it can't attack, can't block, can't even crack its own activated abilities), but the lockdown holds only as long as nobody touches it. Point a spell or ability at the creature and the Aura shatters, freeing it. That self-destruct trigger is the design discipline that keeps the effect blue rather than white: it's a tempo answer wearing the costume of a permanent one. The same clause turns the Aura into a liability against an active opponent, because anything that targets the imprisoned creature (an opposing pump spell, a flicker, a tap effect, a spell trying to remove the cage's victim) ends the imprisonment immediately, sometimes by accident. It rewards reading the board for what can still target through it and punishes the player who forgets that a creature under the cage is one targeted ability away from walking free. That fragility is also why it sits in the disposable tier rather than the reliable one: it buys time and tempo, not a guaranteed answer, and the moment the locked creature becomes relevant again is precisely the moment it's most likely to break loose.