Hi a little bit advice please.

I was repotting my plant today and I found this in the base of my apache plant today and quite frankly I do not know what is.

it if it is a hazard or a benifit.

I took it out and put it in a pot with little bit of soil so I can get a little bit advice

It is about and inch big as thick as a plug fuse when close together it a dark black and apart it a greyish colour.

the plant has had new stems turning yellow the last while so I am wondering if this is the problem or if it just didn't have enough room.

Again a Big thank you in advance.