The idea is to create some sort of a "decoration" biome, to indicate how conventional surface plant and fungal life slowly diminishes with height, and also to provide a "transition" of sorts. It's not supposed to have custom caverns and warrens, only decorations in usual tunnels.
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Horizontal, pleurotus-like mushrooms on walls. Can be eaten.
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Green moss on walls. No particular use.
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Occasional patches of roots on ceilings. Maybe interface it with "vines" mod from plantlife modpack, to craft ropes from it.
Unique ceiling lights for each biome:
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Tall, "arrowlike" white mushrooms that curve back to the ceiling for towercap biome. Quite bright.
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Nodebox fungiwood ropes for fungiwood biome, like big fungiwood trees, but one node and supposed to be tiled vertically. Not very bright.
Unique ceiling lights for each biome:
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Single orange glowing mushroom, for goblincap biome. Bright.
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Multiple braided purple tentacles with plantlike type, supposed to be tiled vertically, for tunnel tube biome. Medium brightness.
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Skeleton stalks, nodebox nodes that look like spore tree leaves and supposed to be tiled vertically. Not very bright.
- Expand cave pearls from second layer
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Expand cave pearls from second layer
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White, long, dense and faintly glowing kelp for sea bed decorations
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Bone corals. Not really bone, but some structure that somehow accumulates calcium from water. Maybe interface it with TenPlus' bonemeal mod
Since the underworld is not an "end" biome now, I thought it would be good to indicate bottom of the world somehow else. What I had in mind is a huge plain realm with one leveled magma (subject to change) sea, pillars and huge diagonal spikes on the ceiling. Maybe rich on diamond ore as to reward descending there somehow. Columns and sea bed are made of slade (or something else impenetrable). This is supposed to be the final layer, not rich on content and players are not supposed to go beyond it. (Maybe even put it to -31000).