C278 Ghosts caught in a jar

I opened the Confinement Web. Looking at the appearance of the net, I could see that it was really quite simple. I was afraid that the person who called out to it was a cleaner. The net was pitch black, and there really wasn't anything attractive about it.

An expert would be able to tell if it was there or not with a single touch. Judging by the material it was made of