SCP Foundation

It’s a woven basalt textile with the bottom side being void to any light or reflection. When any surface comes in contact with the bottom of the textile, it will be destroyed with no trace. The size of the textile tends to change constantly and randomly, but only slightly, except for a certain event in which the textile grew up to 7x7 meters. I would think this would be Euclid do to its spontaneous size changes, and it would also be very tedious to contain it. I have started a sandbox for it, it isn’t finished, mostly because it’s 3 am now. Thanks for reading, any feedback will help. I’ll check the replies in the morning if there are any.

When any surface comes in contact with the bottom of the textile, it will be destroyed with no trace

So… it's pretty much the standard Power of the Void trope: https://tvtropes.org/pmwiki/pmwiki.php/Main/PowerOfTheVoid but as cloth.

Also, what happens if someone folds the textile in half, so that two sides of the "void" face each other?

The size of the textile tends to change constantly and randomly, but only slightly, except for a certain event in which the textile grew up to 7x7 meters

Why? What's the point of this effect besides to just mess with the Foundation and make it more difficult to contain?

I personally don't really think this will do well on the site, since it's a pretty straightforward generic magic object that seems solely to exist to be a pain to contain, and we see a lot of those get posted and deleted pretty much every day. It's predictable and not super exciting, and the audience quickly tires of those.

Maybe take a look at this essay on how to make the classic "thing that does a thing" premise work before revising the concept here. I personally think it's going to take a fair bit of revamping to make this mainlist-ready.