Thank you very much for your votes! :)

This will replace most textures in Oblivion pains. Interiors and exteriors.
Things get darker and more extraterrestrial or unreal or evil...
Oblivion will be like Xenomorph/Alien hives and for that I also included flesh containers with facehuggers inside.
To see the facehuggers, you need these http://www.nexusmods.com/oblivion/mods/42180 textures.

There also is a download with only the cave textures and new lava-rocks. Facehugger included.

Optional Alternatives:
Towers have no black structures and are brighter. Switched two ground textures for nicer tiling. Spine texture is different.
If you want to replace or delete tower textures, they are all in folder "citadelexterior" with the words "deck" and "trunk" in it.
"LavaRockCitadel01" is the spine texture.

I'm not a fan of big textures in low quality, so mine are not HQ and never exceed a size of 1.4 MB.
I also make no Alpha channels if not needed, to keep sizes as small as possible. Just to warn you.