There's a fungus among us! Or even two!
I was minding my own business, building underdark areas for my PW, when I realized that there just weren't any models for certain underground hazards that made me think of those old D&D sessions. So, I made them, based off old Monster Manual descriptions and my own ideas.
I wanted my shrieker to look the part, so I looked at various illustrations, found and modified some textures, and went to work with gmax to create a completely original giant mushroom. Then I added the "speakers" that have always been a feature of these harmless, yet deadly in their own way, fungi. I went with purple as their top color because of another type of fungus they're often found with.
Violet fungi are, of course, purple. It's right in their name. I started with the shrieker mushroom, enlarged it a bit, changed up some of the textures, then swiped the animations from the really, really old Roper model that's in the CEP (not sure of the original source right off hand), because violet fungi are violent fungi.
So, there you go. Two new creatures for killing your module's/PW's player characters while underground. One to attract attention, one to give it.