Scientology holds their non-newbie teachings as, essentially, trade secrets. You only get to see them after you pay a lot of money to "advance" in their ranks. Somebody - presumably a disgruntled insider - started publishing some of their texts on alt.scientology. Scientology tried to stop them by automated (or very rapid human) cancels, with forged "from" fields. Posts on the board got "visited by the cancel bunny". Then people calling themselves "rabbit hunters" tried to figure out who was the source(s) of the cancel messages.

But it got knarlier than that. Scientology's texts were copyrighted; they had police seize the servers of people who put copies of the texts online.

Wired had a good write-up: https://www.wired.com/1995/12/alt-scientology-war/

Around that time, I was working tech support at an ISP and our NNTP server went down - I got a call from a customer who was worried their posts on alt.scientology had caused a DOS attack. Checked some things, oops, no, we had just run out of disk space. Got the sysadmins to clear up some space and the customer was soon back at their flame war. :-D