We thought this looked kind of like bacon:

OHMYGODSOSPOOKY!

I forget what this is called, but it's really rare (the vertical straw-like bit, not the brains-like bits)

Cave popcorn:

This looks like guts or something equally gross...

And this is actually called "cave bacon" because it really looks like a strip of bacon. The right amount of water coming down at the right angle with just the right minerals will create this ribbon of bacony-goodness.

-Lily