A twenty-one foot monstrousity of bone, muscle, fangs and claws. It's about fifteen foot wide, and so massively armoured and muscled it can basically crush, well, everything in it's path, and it's virtually impossible to kill with anything short of strategic-scale munitions. It's massive, broad back is armoured with vicious hooks, it's hands are hideously oversized, four-clawed talons, as are it's feet. It can walk on two feet or four, for extra speed. A stabilising tail extends out the back of it, heavy-bladed spines jutting out of it.
In short, you can't stop it. You can't hurt it. You could blind it, but it's other senses simply adapt. It can burrow, it can crash clean through most buildings with disregard, and those it can't, it can climb. It's capable of making fifty-foot leaps, and the oldest specimens can fucking well fly.
It's called Rolling Thunder, and it's a thing of wealth, and taste.