they called the Worm. Three cutting heads with three beryllite tipped rotary hammer drills each - and in the centre of each one, a plasma jet to slice through metal. The Worm packed some awesome power but there was a problem; it wouldn't exist for another 4000,000,000 years!
Gordon wasn't going to wait. He picked up a handy sized granite chunk and called up the shaft, "Need any help?" Meanwhile, the ghouls were boarding a train to nowhere and singing "One Way Ticket To Hell And Back"