HarryRocks101
The mammoth like creature, 12 ft in height, laced in an unknown metal with huge, thick wall like arms in front of it as it throws fire, scorching the walls, floor and ceiling black like tar. It has no problem marching through the Mrrshan rock men like a bulldozer, their forms on do little to the thick armour of the beast; they're just denting it so far. The appendages they're trying to rip off just swing at the Mrrshans like a big baseball bat
And as for the gunfire? It does little in terms of damage as the skull and most of the skeleton is covered in armour. It continues to charge at the more squishier prey, completely ignoring the Mrrshan force
However, one of the Mrrshan left behind in the beast's rampage notices an exposed spine, however, its only exposed so low down. Ripping it could disable its back lags, meaning its movement could go at a crawl.