Advise on my mine

Question

I'm building an old west mine. My goal is for the mine to burrow into a mountain with tunnels and miners inside. The front view will be railroad going into the entrance with a light bluish gray foundation. the back view will be of inside the mine with miners, gold deposits, maybe some spiders and other creepy crawlies. For the mountain itself, my current plan is to play a series of receding facet pieces on either side topped with some 1x5x4 arches. Here's some pictures of what I've got so far: google link.
My questions are

• Do you have any advice for building the cavern into something closer to a quarter sphere - more cavernous, and less like a pyramid?
• What are some good creepy things to put in the back of the mine, besides spiders?
• I'm considering putting in a small body of water in part of the mine. Is there a way I can put some creepy little tentacles coming out of the water?

Answer 1

Do you have any advice for building the cavern into something closer to a quarter sphere - more cavernous, and less like a pyramid?

Use a circle generator tool (like this one) to plot circles of descending diameter, which can then be built on top of each other - resulting in an igloo-like structure. A few irregularities could help the finished model look a bit more organic.

What are some good creepy things to put in the back of the mine, besides spiders?

• Ants
• Bees
• Demon fish
• Bats
• Owls
• Alligators
• Frogs
• Rats
• Scorpions
• Crabs
• Snakes
• Lobsters
• Octopi (or octopuses?)
• Snails
• Evil pixies
• Dragons
• Tentacled slimy alien headclingers
• Small rock monsters
• Large rock monsters
• Minecraft creepers (crawling)
• The one singular killer beast of Caerbannog

I'm considering putting in a small body of water in part of the mine. Is there a way I can put some creepy little tentacles coming out of the water?

Sure, just add a spiked vine to a trans-blue jumper plate. Or to have a larger tentacle, build the water with a 1x1 part missing, and add an elephant tusk/dinosaur tail/alien tentacle part to a cone set in the 1x1 hole. Other parts could act as tentacles as well.