Mycelium Stag

A large stag, dead but walking, puppeted by a pale mycelium that threads through its hide and re-knits flesh as it is opened. The eye sockets are empty, with fine white fibers hanging from the orbits and tracing pale lines down the face along old wounds the hide has long since grown over. The body is ice cold and slick to the touch. The mouth hangs half-open. The nostrils do not move.

In motion the creatures walk in jerky, aimless patterns until something disturbs them — at which point they charge with the full weight of an elk and bowl the target prone. They shake their racks to release fine clouds of spores that poison anyone caught in them. They make no sound. They take wounds without flinching. When one is killed, the mycelium does not die with it — it peels off the corpse and crawls along the ground to the nearest infected body, thickening the weave already running through that one.

Past the forelimbs and ribs, the host is still in there. With speak with animals tuned carefully past a wall of static, a scrap of consciousness remains, pleading to be killed at distance and not allowed to spread the contagion at close quarters. Behind the static — closer to the source — a different voice speaks: "MY COLLECTION GROWS."

The strain operates out of the mountain monastery north of the Great Tree, in what was once a house of the Order of the Long Death. The voice behind the static is the Gestalt, an Underdark entity the order built the monastery to cage. Fire makes the growth uncomfortable but does not destroy it.