Honestly, the first time I got a look at the Scrin in Command and Conquer 3, I though “Yeay! The Steltek!”, but then again, their units had more of a “Nephilim” feel to them.
http://www.youtube.com/watch?v=T1VfzdbqpAw&playnext=1&list=PLD102B945759A6A50
I suppose the Steltek picture looks a little like the Gravmind from Halo 2
http://www.youtube.com/watch?v=Zku2tIoSbfs
Little shop of horrors indeed:
http://www.youtube.com/watch?v=bLO7IxKwruc
There was a series of Wing Commander fanfic stories (of varying quality) centered around the Steltek becoming the big-bads threatening the galaxy.
From what little I was able to gather, they were described as follows:
They have “bulbous bodies” with “membranous tendrils” which trail behind them.
There’s a description of a mass of intertwining plant-like biomechanical feeds that run into every pore of their body, though this is probably a life-support system.
It also mentioned that movement of their head tendrils is a type of body language, such as the twirling of head tendrils was a sign of submission and respect.
They apparently have ocular nerves which can connect directly with ship to see what the ship’s sensors see, and retinas which “shimmer brightly” in the dark, and can apparently become “age-clouded” in elder beings. Its also mentions them using Infrared Heat Spectrum representations in lieu of VDUs, suggesting that they probably see into the infrared range. This is also supported by the fact that their typical habitats are described as being dark and mist-laden
Again, this is all fanfic info, so take it with a shaker of salt or two.