Check out this guy that creates entoforms with Blender (a cool and open source 3D app, you know, "Big Buck Bunny" and so on) and his own special add on. What's an entoform? Well, you'd have to read his blog but in short it's some weird insect-like creature.
Check out like a zillion generated entoforms/insects here:
http://www.youtube.com/watch?v=v4Up8zMtWl0
And the blog here:
http://www.macouno.com/category/projects/entoforms
Actually, the guy has started 3d printing the forms and pinning them like real insects, which is somehow cool in it's own way :)
What's this all got to do with Shadowrun? I don't know about you guys but I'd feel just great generating one or two such forms and scaring the shit out of my players with some cool render, describing it as a dark magic creature, or maybe a toxic path mutant giant insect that they just woke to see in their room in the middle of the night, nibbling on sammie's cyberleg :)
Unfortunately, the add-on is not yet released in public (too unstable) but it's gonna be released once it matures, and by the early look of it and the sheer amount of creatures generated for one short video above, it looks like generating them will be easy and fast, which is just the way I like it. Not everybody has days to draw their scary monsters you know :)
Just after having looked at the video I have a couple of good ideas for dark toxic insect-monsters in my head.
Hope this gives you some too!
Sweet dreams