Bound by Moonsilver

Pacifism that follows the threat. Most lockdown auras pay for their cheap rate by being stuck: they pin one creature, and when that creature dies or gets bounced the enchantment goes with it. The sacrifice ability rewrites that bargain by letting the aura jump to a new target, so the cost is no longer mana but board presence: each relocation eats one of your own permanents, and you only get to move it once per turn at sorcery speed. That sorcery-speed gate is the load-bearing restriction. You cannot ambush a freshly cast threat at the end of an opponent's turn, and you cannot redirect the lock mid-combat to suddenly neuter an attacker; the move happens on your own clock, as a deliberate act, against a board you can already see. The "can't transform" clause is the detail that explains the name and the card's specific reason for existing: against a format thick with werewolves and other double-faced creatures, this freezes them on whichever side they happen to be showing, denying the flip the threat was built to deliver. Stripped of that context it still reads as a pacifism with legs, but the transform line is what makes it a purpose-built answer rather than a generic one.