If every WMD was powered by WD40, there would be a lot more WMDs in my grandfather's closet. Still, it is amazing how easy it is to make something terrifyingly deadly out of everyday materials.

[hider=things you should never make unless the undead start gnawing on your leg]
PVC pipes + WD40 + ammo of your choice = cannon capable of penetrating a car door
gasoline + foam cups = napalm capable of burning pretty much anything
bleach + ammonia = chlorine gas capable of making every person nearby suddenly very dead (not very effective against the already dead)
lighter + spray paint / hairspray = flamethrower of awesomeness
supersoaker + gasoline + lighter = even more epic flamethrower of awesomeness[/hider]