How to ban a user on a site that does not want it?

Question

Computer networks

There is a forum and one stubborn user who has been annoying with his presence for several years. Already several hundred accounts have definitely banned him. He has already learned to use both proxies and mobile Internet and all sorts of TORs and anonymizers. Every day he creates several accounts and is not lazy. And we ban him with one click and all his messages are deleted. Those. registers in order to have time to write something in an hour or two, arrange a holivar and have time to spoil someone.
Here's how to ban him? Maybe there are still some magical things besides massacre?

Answer 1

shotgun