i found this when i was going over my old world to see what i should keep and what not when moving to my new smaller world (1.92 GB --> 300MB (-_-)... ).

its best described as being a asteroid crash landed on my world spawning evil and tainting the world with obsidian roots (not included sorry). itbuild up in 3 segments, outer ring, middle arias, inner lair/sphere/comet etc....

place it in your world and have fun beating silverfish, when in the middle youll face ghasts to....

ps, place all the way down to bedrock level to have the bedrock fog and particles give an even more eerie feel. can also be placed undergound but make it a spherical cave with a hole in the roof to simulate the crash a bit....

if you use this please give proper credit, for the rest? have fun with it.

Additional Notes

mcedit .schematic only.

images are renders made by a program called chunky.