“ On a location with numerous webs, and at least one big spider, there is a something inside a cocoon. It is humanoid in shape, still moving. If the heroes free it (not before they kill or drive away the spiders), they meet a ... zombie!
The poor zombie wandered the dungeon alone, and tried to kill a big living creature (= a spider). The spider used the usual treatment, even if this victim did not look tasty. The zombie can be easily killed as any other zombie. It got but several doses of spider-poison, so can be something worth if it is extracted. You can mention to a druid or ranger the fact the spider had no poison anymore.”
“ The peasants of the wood use crudely carved symbols to ward off wolves. They think the symbols are emblems of purity and goodness and that keeps the wolves away. The symbols work, but not for the reasons the peasants believe...
The symbols are actually arcance evil symbols which the wolves know and fear, but to which the peasants are oblivious. So how gullible are the peasants going to be when a strange horned man displaying the symbols on his shield turns up and asks for their allegiance?”