The violet fungus first appeared in first edition in the original Monster Manual (1977).
The violet fungus appeared in second edition under the "fungus" entry in the Monstrous Compendium Volume Two (1989), and reprinted in the Monstrous Manual (1993). The Cormanthor violet fungus appeared for the Forgotten Realms setting in the Elminster's Ecologies boxed set (1994).
The violet fungus appeared in third edition under the "fungus" entry in the Monster Manual (2000), and in the 3.5 revised Monster Manual (2003).
Violet fungi resemble large, purple fungi with tentacles. The violet fungus shares a symbiotic relationship with the shrieker in order to hunt. The shrieker emmits a high-pitched wail to lure prey, and when it comes, the violet fungus attacks with its tentacles.