Answer:
Disgusting creatures that would survive a nuclear strike.
The homes of tiny creatures that collect in corners if you aren't vigilant about dusting.
When it was young, it had a tail. When it grew up, it had knees
While I did live, I food did give, which many one did daily eat. Now being dead, you see they tread me under feet about the street.
In all the world, none can compare, to this tiny weaver, his deadly cloth so silky and fair.
What is always coming but never arrives?