Answer:
As soft as silk, as white as milk, as bitter as gall, a thick green wall, and a green coat covers me all.
What measures out time until in time all is smashed to it?
Hard to catch, easy to hold. Can't be seen, unless it's cold.
An open ended barrel, it is shaped like a hive. It is filled with the flesh, and the flesh is alive!
Hold the tail, while I fish for you.
I run through hills. I veer around mountains. I leap over rivers. And crawl through the forests. Step out your door to find me.