“ 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.”
“ 'Look, lad! You see the streak of glowing green off the larboard bow? Them's the bright waters!'
While the lad peered intently at the eerie glow, the old salt continued. 'Entire ships have been lost to the Bright, lad, for once you let it surround you, you'll never touch land again!'”