“ 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.”
“ As they are travelling along the road, the characters come upon a carriage under Goblin attack. They rush to the rescue and defeat the attackers, but the owners of the carriage, a man and a woman, are already dead. As they rummage through the corpses looking for gold and valuables they hear a noise coming from inside the carriage. Investigating, they find a young child hiding underneath one of the benches. What will they do with this orphan?”
“ You find a patch of edible funghi. They taste well and all, no ill effects. UNLESS you consume some beverage, even 3 (three) days after eating it. Then you become really sick with pains, vomiting, all the fancy stuff. As a gift or good meal, it could be a cruel joke or to make sure the heroes spend their time focused on the mission. And the fine soup you had in the inn yesterday could have some in.
(Inspired through a real-world fungus. Was really used to cure alcoholism.)”