What is this part called?

Thank you very much for the reply boss.

I took your advice and jacked up the strut. I hiked up the bellows and sure enough, a little plastic son of a bitch was all malformed up in there. So, as evidenced in the picture, I popped that sucker off with the crowbar. Nice and quiet now. I am guessing its function is to keep gunk out of that shiny strut? My new question: is it alright to drive around for a few days with that upper strut bearing thing off, until I get the new one? Thanks for the help man.

https://imgur.com/a/G7J7kNP

Thanks for the reply Submariner.

You are correct, I have an ESC, not an ETC. I don't know how I got them confused, I have known this. Know I know it doubly. As for the oil I had sprayed some silicon lubricant on the stut before I removed the dust cap, it's not coming from within the strut. I didn't know the ETC and the ESC were so different. Anyway thank you for helping me out and for giving me all this info, it's much appreciated.