A jacket benefit that can open a locked exit by consuming one of Carl's bones and destroying the garment.
Carl plans to surrender the Royal Court's ordinary key to Imani through the final Flee rule. He believes his jacket can then invoke Mysterious Bone Key to open the stairwell anyway.
The effect costs the jacket and one of Carl's bones. The specific bone is not selected or known, so the physical consequence could range from manageable to catastrophic. Donut objects that both the garment and every bone are important, but Carl accepts the risk to keep both squads alive.
A dark jacket opening a locked door as one glowing bone dissolves into a key shape.
The benefit gives Carl a costly independent exit path that makes cooperative key surrender possible.