How about giving spider mines a bite that causes an explosive syndrome and the thing that I suggested? if you were to make the stuff that globes the burny gas really brittle it might explode the spider mine too. (EDIT)I don't even know if it's possible to make the spider mines bite make someone else explode.
not explode...but so far I can make them boil. I'm still having trouble getting the little buggers to kill themselves though. I know it's possible...I just need to work more with materials.
(Fakeedit) Could there be a mutant class similar to The Master on Fallout 1? or Harold on Fallout 1 or 2?
The problem with The Master is that he/it is more like a building than a creature...a giant pile of meat melded with circuitry and machinery taking in normal humans and animals and spitting out mutants, but right now...creature producing reactions are impossible...and Deon's mutants are fertile, so don't really need The Master anymore...
Harold...we actually suggested Harold-like half-plant mutants when Deon was thinking about adding an elf-like race, as in a world a thousand or so years after the war, most green plants are probably Bob's descendants, and the Treeminder race would probably take offense to you chopping down their cousins, however...they would also be prolific traders, buying and selling almost anything they could get their hands on. Basically...they would be effectively immortal like elves, but their skin would be covered in patches of bark or have twigs poking out...and maybe have a caste that could be "milked" for a rare hallucinogenic sap that they use as a drink. Could possibly have an underground tribal version of them too...except they are slower and part mushroom (though...underground civs don't trade do they?)