Cactus Dan was a character. He created a set of plug-ins for Cinema 4D called CD Tools, which were invaluable for character rigging. His website featured a colorful-looking desperado, complete with cowboy hat and handlebar moustache, plastered on a "wanted - dead or alive" poster, that I presumed was a work of fiction.
It turns out that the graphic was a photo of the real Cactus Dan, who lived in Utah, rode horseback and hung out with goats. I know this now because I was in the process of emailing him a question about one of his plug-ins, only to discover he passed away in September. I'd corresponded with him on several occasions and he was always quick with a knowledgeable reply.
You can read more about him, and see photos of his colorful life, here:
Mostly, he writes for a living.