That's a decent starting point. Picture something about that size and with that same penchant for tunneling underground only to pop up at the most inopportune time possible, except its mouth opens on four vertices instead of the usual two, it has far too many fangs for most people to be comfortable around it, and it's more organic than mineral.

If you're imagining a nine-metre worm with a lotus full of teeth for a face, you're on the right track. That's one of my personal favorites.