Indeed. This happened a while back. We had a friend of our daughter's watch the house and tend to the cats while we were on vacation. He was clueless about how to properly dispose of cat litter (it goes in the trash can), so he flushed it. We use wood pellets instead of clay. when those pellets get wet, they expand. That mass of expanded wood pellets was extremely tough and would not yield to a power auger. If you wanted to sabotage someone's sewer, this would be a way to do it. Not that I would condone or recommend doing this.
I ended up pulling out about 5 feet of cast iron pipe and replacing it with ABS. The pellets didn't break the pipe, I did that with a sledgehammer after I pulled the section of pipe outside. The only silver lining is the crawlspace under that part of the house is tall enough to stand up. From there. the sewer dives under the downstairs slab floor and if the clog had happened under the slab, it would have been very bad news.
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He still owes me a bottle of scotch.
