Recreating the rock cycle
Here's an idea:

You can use dark chocolate and white chocolate. Use a grater to create "sediments": layers of alternating grated dark and white chocolate.

Now heat them up just before melting so you can stick them together with pressure, preserving the layered structure. Now fold them. There's your "metamorphic" rock.

Then, just melt the entire thing to create some chocolate-lava flows. Grate them again and eat!