Used to bush hog as a side gig for many years, and I think literally hit everything you can imagine. Cinder blocks, rocks of every size, snakes, animal carcasses, rebar, wire, pipe, fence, stumps, a smashed shopping cart, brake rotors, you name it. The worst ones that stand out that caused the most damage or most amount of work to fix are; barbed wire, a cylinder head from an engine, an ungodly amount of fishing line, rope, and cable of all sorts. The one that made me feel physically sick was a nest of bunnies.