The Wall Choir was a collection of ponies that have been melted and fused together in a single living, breathing mass. The Wall Choir was encountered by Blackjack in Horizon labs.
The Wall Choir was a wall of flesh, comprised of ponies that had worked at Horizon Laboratories. The ponies were fused together by flux contamination, becoming an amalgamation of body parts, metal, and flesh. They covered the walls and floor of an underground laboratory located beneath the foundation of Horizon Laboratories.
The wall was sentient. It emitted horrifying screams and tried to force Blackjack to scream along with them. They began breaking through her barding and trying to fuse her to itself. The wall revealed the shells of Folly were made of something that resonates its own song, one different from their own. They also claimed the Goddess offered a cheap, artificial form of their own unity.
The wall pulsated and spoke with multiple voices, sometimes answering or mocking Blackjack. When the wall tried to forcibly fuse her to itself, the Dealer got her to activate S.A.T.S. so she had time to think about what they wanted. They kept urging her to sing with them, so Blackjack used her PipBuck to play music which calmed the living mass down and allowed lucid thoughts through.
The living mass of ponies were grateful to Blackjack and instructed her on how best to kill them. Rampage organised the explosives and gasses that would kill the Choir while Blackjack continued to play songs and keep it sane until they had finished. The lab the wall choir was in was engulfed in flame, killing it.
Aside from screaming, the wall could grab and fuse ponies to itself, forcing their victims to join in their macabre choir.
- The Wall Choir might be a reference to the Dead Space necromorph known as a Guardian, a just-living person fused to the wall by the necromorph virus and who continually shriek in agony.
- The choir also seems to act like the Goddess by absorbing ponies into itself.
- Their speech of a song is similar to Daedelus & Nathan Hale from the game Resistance 2.