What is that!?!

For a couple of weeks this bush attracts my attention as I drove along, I did not really have the ability to look clearly. I was wondering if it's a spider web or a fleece. A spider web seemed to be to gigantic, but on the other hand, who now hangs a curtain over a bush so badly to reach ... Today I plucked up courage and agreed closely watch it and it turned out really to be a mega spider web!!! And at short range you could see that a lot of caterpillars were scrambling on the outside. I have never seen something like this...