“ Sessiliths (name based on the word sessile) are gargoyle-type creatures which are stationary, attached to the stone of whichever foundation they are bound to. Though they can move their extremities and limbs they are unable to move away from their particular perch. In lieu of swooping down and attacking like their mobile cousins the gargoyles proper, sessiliths are equipped with their own brand of mischief. The creatures are all able to verbalize and thus usually hurl vile insults and curses upon passersby. The cumulative effects of dozens of sessiliths cursing, screaming, and speaking in tongues, can have an effect of temporary confusion (or even discord) in those forced to listen to the shrieking stone gremlins.
Additionally, most possess the ability to 'spout' or spit forth various undesirable projections, such as tar, boiling water, or even acid. While they can usually be avoided easily enough or even destroyed (their 'bodies' feature the same defenses as gargoyles), sessiliths are usually placed in such a way as to hinder all trespassers and interlopers, narrow corridors, claustrophobic tunnels and other related 'gauntlets', where they cannot be easily avoided. Like gargoyles, sessiliths come in all sorts of grotesque shapes and sizes, though they tend to resemble tiny horned devils, demonic amphibians, or simply distorted faces and heads, more often than not.”
“ 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.”
