“ 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.”
“ A Cloak of Shadows that causes mushrooms to grow in its own shadow. A crouching theif might find himself in a ring of poisonous toadstools, an interesting thing for a sentry to find after the thief has left hiding place.”
“ Most large mammals, such as elephants, rhinos, and their modern ilk are ill-suited for domestication, but that doesnt exclude their use as engines of war. Rather than raise and train the Mammoth from birth, Mammoth Handlers instead capture the wild Mammoths at a young to juvenile age and train them for war. These animals are draped in armor and are unleashed as living war machines against the foes of the Mammoth Tribe.”