Biological weapons! And the best place to develop such a thing is in a ghetto.
Now I have your attention let me explain
There is a thing called a slug ghetto. You collect a bunch of slugs and put them in a confined space surrounded by nastiness. Sooner or later you will have a slug that is infected with nematodes and when you put that slug in the ghetto, then all the other slugs will become infected.
Create a nasty enough ghetto and it will poison the entire slug community.
Anyway, here is an already existing thread on urban planning for slugs:
Slugs in da hood