It was a difficult clip to exam... Here is what I thought about it.
I think it is the extream image of what human races has walked and what might happen.
Varmints represent humans, at first, they had nothing and very curious with anything that happened around them, and had respect to it as well. As time goes by, the black varmints builds a mass of buildings and the gray ground sniffs the life out of the tree, this represents that what we have used, what we have dissolved as we advance our technology. From that, the air becomes very dirty and slowly poisons the black varmints dies from it. The plant that varmint was holding preciously is the heart to love nature, and the the jellyfish like creature represents nature, I guess. It protected the varmints from pollution.
Therefore, I think this is a clip that tried to convince us to admire nature more, and come back to the life that things are much more simple.
