It was a kayaking trip not a bike tour, but I once slept on what was left of a dead dog. We made camp after dark next to a river that we planned to run the next day. As is my habit I didn't bother to dig out a light. The site was one of the impromptu dumps that are so common in West Virginia. Well I saw that there were some chunks of wall board and some "insulation", so I brushed aside most of the insulation and arranged the wall board to sleep on.
When I woke I was looking at a dog skull inches from my face. The "insulation" was actually fur.
I have slept in quite a few impromptu dumps and an occasional cemetery, but the dog skull site was probably the most interesting.