Detention Vortex

White has always struggled to answer the biggest threats cleanly, so its removal often comes with a discount that leaves the door open: Pacifism-style shackles that neutralize a creature without exiling it, Oblivion Ring effects that can be undone, Banishing Light that a savvy opponent can crack in response. This one takes that tradition and hands the escape hatch to the enemy directly. For a single mana it shuts a permanent all the way off (no attacking, no blocking, no activated abilities, which lets it answer far more than creatures), but it writes the leash it can be freed from into the text: your opponent, and only your opponent, can pay three mana to break it, and only at sorcery speed. That last restriction is the whole balancing act. The sorcery-speed clamp on the release means it can't be used as an instant-speed combat trick or a stack-based rescue; the opponent has to spend a main phase and three mana to reclaim their permanent, which is a real tempo tax even when the removal is temporary by design. It converts a permanent answer into a Rube Goldberg tempo play: you get the cheap shutdown now, they get the option to buy it back later on their own clock. A neat inversion of white's usual bargain, where the color that hates to give up removal builds the giving-up right into the card.