Adventure Location - Underdark

Short location for an encounter, ambush or distraction. Options for a possible interesting extra.
The Underdark is a place of twisting tunnels, constant darkness and strange magic. Encounters might occur in a forest of fungi, amid giant stalactites or by the side of a gaping chasm. It is a place of elemental earth and gates to far realms. Home to fungi creatures, the dark elves and aberrations from the Far Realms.

tools for - dnd5e encounters location underdark

terrain: Terrain Type:

A tunnel-ridden cave with large stalactites (it is associated with aberrations)
A shore of a muddy lake and a patch of phosphorescent edible mushrooms (close by is an area of pink edible bulbous mushroom)
A strange shrine to a power of nature and a fish-filled pool with many insects (there is smoke from a fire)
A brook feeding into a river (the area is associated with a powerful dark elf)
A tunnel-ridden cave with large stalactites. There is a reed-filled stream fed by a spring with an enchanted statue of a pleading tentacled-monster (nearby is the fresh corpse of a rat)
A fungi-filled pool surrounded by granite (there are numerous fireflies)
A pillar of glittering volcanic glass surrounded by sandstone (by a low cave with large stalagmites)
A ford over a sparkling river (the area is disguised by a hallucinatory terrain)
A tunnel-ridden cave with large stalactites (there are the bones and carapace of an scaled insectoid monster)
A set of stone steps leading up a cliff (which is associated with a dangerous snake-monster)