Q.What is the brown prickly stuff growing all over my euonymus shrub and how do I stop it?
I have a golden euonymus shrub; not ground cover. I’ve had it for 15 years and have never seen this brown stuff before. It “reaches out” and attaches itself to the next branch, the next, and so on…until multiple branches are bound together. This seems to slowly strangle every single limb it entangles, eventually killing the whole bush. I first discovered it this past spring. I spent hours and hours with a scalpel-like blade, cutting through the large masses of brown that had entangled the main branches at the base of the shrub, separated/freed the branches from one another, and then scraped all the brown stuff I could off the stalk of the limbs (small patches of it can be ripped off the skinny limbs like a bandaid, but the huge patches at base of shrub had to be cut off, like peeling the skin off an apple). Most of the bush was so fully covered/entangled in the brown stuff, and had already been so compromised in health, that I just had to cut the top growth of the bush down, nearly to its base. I thought it would die, but it didn’t. Grew back quickly and beautifully!! But this past week, I see the brown stuff is back and it is everywhere once again. It’s not nearly as advanced as last time, but I’m afraid of cutting it back so deeply before winter strikes. Also, the bush obviously needs some kind of systemic treatment to be rid of it for good (at least, I’m hoping treatment is available). I’d be so frateful for any information and suggestions/solutions you can give me. Otherwise, I suppose the whole thing will need to be uprooted and I’ll have to start anew in the spring.

Certified GKH Gardening Expert
It may be a parasitic plant, possibly a species of "dodder." If so, you are doing the best solution by pruning and hand removal.
https://www.gardeningknowhow.com/plant-problems/weeds/dodder-weed-control.htm
I suggest that you contact the OSU extension service or master gardener program for local information. https://extension.osu.edu/ask-an-expert