Once long ago on a MUP, I came across a huge Black snake. He'd been hit and was ruptured. I felt pretty bad for him (her). It was a fine specimen. I helped it over to the bushes where it could die in peace.

Last year, on the way to work, I rounded a corner on a very short section of MUP that I used. Suddenly, before I could stop, I rolled through some stinky yellow and clear liquids that got all over me, my bike and bags. I think it was some separated paint. Smelled bad, ugliest yellow I'd ever seen. It looked like someone had broken a fresh dinosaur egg in the middle of the path. Yolk and clear white. I still find flecks of it on the bike (blue one in logo below.)

Other than that, the usual shoe, hat, shirt, bottle, dead critter, bra, is all I've ridden by.