Phantom FungusDreamwalker of Corruption

What Ascogenea touches, grows. What Ascogenea touches, rots. What Ascogenea touches… is changed. This applies even to those creatures that she has made entirely on her own–even the spawn of perfect corruption cannot resist the touch of true chaos. When the spirit of the Dread Queen touches one of her dark gardens in the Depths, sometimes the whole thing is swept away in an instant, caught up in the dark power of her dreams. And sometimes, something is left behind … a Phantom Fungus…

Read the entire ecology and get the full 5e stat block in Mortal Arrow’s supplemental booklet:

Warren of Vile Fungi: A Guide To Fungal Horrors, Hazards, and Curiosities found in the Depths