a flow of molten 'lava'
(..) Bumpy. - Is everybody all right? - Yeah. Where are we? What's that light down there? That's lava. It's magma, and it's rising. There's supposed to be water in this tunnel. Steam, water shooting up. We're too late for the geyser, we missed it. (..)2008 Journey to the Center of the Earth
(..) Daddy." Goodbye, Max. Come on. According to Max's journal... ...we're here in this giant air pocket that's surrounded by lava. And during periods of intense seismic activity... - Like the one we're in now. - That's right. - the magma that surrounds us... (..)2008 Journey to the Center of the Earth