Would it be possible to make a dynamic tunneling worm thing, as seen in Effing Worms? I'd like to try to do this with some kind of dynamic chain script, like in the Hammer Ships mod, combined with a simple floating actor (that is possibly only affected by gravity above ground, I think that's possible) with some various AEmitters to make tunneling cleaner, if needed.

viewtopic.php?f=61&t=19312
This is pretty much what you want.