Inside a shifting metallic reef-bastion, one infantry carrier must deliver a singularity core to the growth-heart.

The structure seals corridors, moves its own mass, absorbs bodies and armor, and the core will only arm when every squad life-sign is gone.

The deeper the carrier goes, the reef turns the mission into a slow mechanical trap.

Gravity fails, corridors collapse, drones emerge from the walls, and the suit begins to die around him.

Then the truth surfaces: command never planned an extraction, and the device on his back is waiting for his heartbeat to stop.

This is "The Living Bastion" by Sascha Schmidt