“ A small, primitive village has yet to discover fire, which is a good thing because there are highly flammable (but not otherwise dangerous) gasses in the air. The heroes, blissful in their ignorance, don't know that and think it a wonderful idea to show the locals open flame.”
“ THE GNOMES OF UDNALOR: Part I
Upon entering the deep underrealm of Udnalor, one must first pass through the upper halls, which were the residences of the gnomes in days of past glories. Now they have abandoned the fading tapestries to the worms and moles, and an uncanny silence reigns, laid over the oaken tables like the thick layers of dust and humus.
There may be creatures which now inhabit these areas: nests livid with giant maggots, rats and other vermin.
The watchtowers and passageways which lead to the Overground are frequently trodden, however. After all it takes a great many small humanoids to hoist a single giant rabbit corpse back through the fathoms of earth.
The gnomes primarily hunt giant rabbits with bows and arrows tipped with the subterranean poisons concocted by their best alchemists.”
“ Real World: some Indians in the Amazon treat their eyes with a traditional potion applied with palm leaves. Brutally painful, the drug alters vision, giving the jungle's dense green walls greater texture and dimension. You could adapt this to desert or swamps, or other hard to navigate regions.”