Corrupted Morgue

It starts underground. Something in the soil shifts, the Infection pooling where it should not, saturating the earth beneath a settlement until the weight of it begins to build. A Morgue structure starts to form on its own, not built by Necrologist hands but grown by the Infection itself, reaching upward through rock and root like a blind thing looking for air. Then it fails. The structure collapses before completion, the walls buckling inward, the chambers folding. And the Infection, patient and relentless, begins again. Reinforces the ruin. Builds atop the wreckage. Fails again. The cycle repeats, degradation and regrowth locked in a loop that never resolves, and the interior becomes something no functional Morgue was ever meant to be: a breeding ground.
  Corrupted Morgues form for reasons that are distressingly varied. A settlement that performs too many Grave Procedures in quick succession can flood the surrounding area with enough Infectious activity to catalyze one. Concentrated psionic use draws the attention of the undead and accelerates Infection proliferation. Prolonged radiation bombardment forces the Infection to reconstruct itself underground (radiation suppresses it, but the Infection never stops trying to reconstitute). Even a catastrophic failure during conventional Morgue construction can produce one. The causes differ; the result is always the same. Pustulent chambers filled with fungal growths, decaying biomass, and things that used to be dead in the normal way but are not anymore.
  Detection is a matter of paying attention to the wrong kinds of silence. A Flame Whisperer who enters a Morgue space and taps into the Mortis can, after sustained ritualistic effort, sense what lies beneath: the shape of the corruption, the nature of the threats incubating inside. Multiple Flame Whisperers performing the ritual independently each learn different pieces of the picture. For everyone else, the signs are more visceral. When a Corrupted Morgue is active, any character who dies and passes through the Mortis experiences a modified death scene. A Wahel zombie appears at the edge of the Mortis space, advancing one step every thirty seconds, growing louder with each step. Those performing Mortis Procedures or Aberrant dives encounter the same manifestations, and risk being thrown out of the Mortis entirely with Fractures if the thing reaches them.
  The only way inside is the Lancing Casket: a Necrologist-engineered coffin built from metal and bio-material that inserts a living person into the structure's interior. Five minutes. That is the operating window before forced withdrawal. Inside, the chambers get worse the deeper you go. The outermost spaces may present obstacles or puzzles; the deeper ones are heavy with Wahel and the Morgue's central Infection mass. Multiple teams dive in succession, each clearing ground and contributing work toward deploying the Helscape Catastrophic Stabilizer, a bio-material machine that requires thirty cumulative minutes of activation to render the Corrupted Morgue dormant. Dormant, not destroyed. No known method permanently eliminates a Corrupted Morgue. The Helscape guarantees at least three months of inactivity. After that, the clock resets. If no one addresses a Corrupted Morgue before it matures through a full event cycle, it erupts. The eruption floods the settlement with Apocalypse Grade zombie threats in numbers sufficient to level buildings and force total evacuation. Then the festering begins again, and the next team of Grave Divers straps into the Lancing Casket and goes back down.