Well, am about to send my player into a swamp that has a lot of geothermic activity; so hot gysers and boiling mud; that kind of stuff all set to an Eygyptian theme; pcs are seeking a lost temple of Anubis but do not yet know it it guarded by a tribe of Sobek worshiping men, crocs and werecrocs; I would really like to have the wetlands come alive so could use any hazards or boons that the place might grant; I already have the important mobs down, but any insects or terrain hazard like sucking pools of tar and whatnot would be nice; am thinking to put a lost kingdom of apemen at the other end of the wetlands; maybe the two tribe have constant warfare; but I cannot find any monkey gods so might have to make them up
That sounds like a pretty interesting local. I really like your geothermal swamp idea. I'll have to swipe that concept and place it in my homebrew somewhere.
lol; have fun; am thinking hard about it; thought peeps onheresabout might have an idea or three.
"Swamp Dangers" in Dungeon 126, pp. 92-93.
When I ran Encounter at Blackwall Keep from that issue, I also had the mosquitoes serve as a hazard:
Mosquitoes: Huge clouds of mosquitoes come out whenever the sun is not directly shining (i.e. misty, cloudy, night-time). During these times, characters must make a fortitude save (DC 12) each hour or be sickened for the hour. One DC 12 fortitude save must be made while sleeping or the character does not sleep restfully and is fatigued the next day. Exposure to mosquito bites all night does 1d2-1 points of constitution damage due to blood loss, and exposes the character to Swamp Fever, (Fort DC 13) which does 1d3 Dex and 1d3 Wis damage per day after an incubation period of two days, as the afflicted character is wracked with periodic bouts of shivering and becomes feverish and in serious cases delirious. A +1 or greater natural armor bonus renders a character immune to mosquito bites and their effects. Wearing any armor that covers torso, arms, and legs gives a +2 bonus on saves to avoid being sickened or fatigued, and on the initial save to avoid contracting swamp fever. Wearing full plate or a similar armor that covers all parts of the body grants +5.
Knowledge nature DC:
10 Mosquitoes in the Mistmarsh are more than just an annoyance
15 Mosquitoes in the Mistmarsh are so thick that they can weaken you with blood
loss¡Xthey also carry Swamp Fever
20 The leaves of the shrub known as gnatsbane are an effective repellent to mosquitoes if rubbed on exposed skin. (Survival DC 20 and one hour to find sufficient amount for four doses¡Xone dose lasts eight hours, and the leaves lose their property after 24 hours).
You also might want to check out "Fiend's Embrace" in #121--it's set in cold marshes, but has some cool swamp encounters that you might take some inspiration from.