This dude, he called himself Mr. Hands, liked to fuck horses and film it, but he got overfucked, so eventually he died. This made things bad for other horse fuckers, since this case was the reason why a new law was passed in Washington that banned human horse fucking (zoofilia in general actually).

There was a case of horse sex in Enumclaw, summarized in a wikipedia article (particularly the English mobile version of the site)

Now how they fit six horses into a single courtroom you’re going to have to ask an expert for that one.