The Zygomind is a creature from space that copies minds through an ability to induce a mindscape. It leaves its hosts undisturbed by means of parasitic fungal spores. It contaminated the tree of Zoe, causing her death.
Its connection to the myconoid mind, or Far Realm (Thigomind), is confirmed. It forced the group into a mindscape by a powerful spell, making them live in another reality described as “a dangerous Narnia”. The Thigomind/Zygomind connection is serious and ongoing.