“ When was the last time a character caught a cold or flu? Real people get them every now and again even with solid heating and dry interiors. Your characters are out in the cold and wet, and even inside is not always dry and warm. Imagine having to stop your dungeon crawl, sitting in a tight defensive position, while you all are feverish.”
“ 'Binding the Life Coil' is an ancient quasi-mystical technique rediscovered to prolong one's life at the expense of one reproductive ability. It is a simple magikal technique that anyone can learn (a skill or feat). The promise of near immortality or a lifespan of a thousand years or more makes everyone want to learn it.
This technique has a price though, the amount of immortality is in direct response to the strength of ones reproductive spirit. Those that have never breed will live longer than those that have. The use of the technique makes conception difficult, if not impossible. So you trade the future of your society for the chance for you to see much of that future.”
“ 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.”