It used to be possible as networks could advertise that they owned IP ranges that they didn’t actually own using BGP, which is what’s used for high level routing. This is what China did around 2010 where they allegedly routed all the internet traffic in the world through China for like 10 minutes. I guess somebody could do that and then just drop every packet.

I expect that’s not possible anymore though, but I’ve been out the game a while so I don’t know for sure.