I'm GMing Pathfinder 1e this weekend and my players will be delving through a cave that was once a silver dragon's lair. I want to have a bunch of encounters planned out so that I can stretch this crawl out to the end of session, since we have a guest player who we don't want in the story for too long or too short.
Stuff they will find so far:
-Group of Frost Giants in the entrance. They don't speak common, but are pretty chill guys if a player remembers to cast Tongues.
-SO MANY SPIDERS, while escaping down a spiraling cavern. I'll have them crawling out of the walls and stuff.
-A Black Pudding. Never used one of these, and I don't think my players would know what to do immediately.
-Long underwater cave with some aberrations in it, maybe gibbering mouthers. Also a gigas clam with a huge pearl to lure in the party ninja.
-Big ending surprise - it's not a silver dragon's lair, it's a black dragon's lair, and this whole plot was him luring you to get eaten. Why is this cave so long? Because the black dragon just uses his underwater secret entrance/exit for his schemes.
Party is level 10 and there will be 5 of them, 6 with animal companion. Does anybody know any good encounters for a group like this? Doesn't need to be system specific - I'd love ideas for cool cave traps and stuff.
Hanging lichen "curtains" full of dormant flourescent algae activated by body heat. Mark anybody who has moved through with a nasty neon green glow a couple minutes later. Attract spiders, ruin stealth, bonus to ranged attacks against you. Requires a lengthy bath, strong alcohol or FIRE to remove. May be useful for moving through extremely combustible areas (spider webs, cave gas) or to distract the spiders from the main group... if your players are resourceful.
Raw gems in a cave wall next to an old dwarfish "dibs" rune. The faintest smell of burnt beard. The gems are actually a crystal that reacts extremely exothermically with water, for example when touching skin or (assuming protective gloves) when held up to the face for inspection and breathed on. A good alchemist may negotiate with the salamander living within to make them safer to handle but this requires a bit of a ritual.
A creepy but mostly harmless olm. Getting too close will slow your metabolism and may induce sleep, that's how it keeps its prey fresh. Killing it will contaminate a large sphere of water with its secretions, paralyzing/petrifying everyone inside.