That mystery meat looks more like an intestine....
Rocky Mountain Oysters taste like calimari. They are slightly chewy and, if seasoned properly, are very good. Having a few good beers to wash them down with does not hurt.
I have seen these on menu's in Colorado and in Kansas. I also had them in California.
Thank God I'm not a wuss. When I was a kid hanging around one of the local ranches, they would take these fresh,very fresh, bull testicles and hang them from a coat hanger over the branding fire. They were edible but wouldn't want to live on a steady diet of them.
Years later I had, on occasion, servings of them prepared more or less the way tennyucks recepie indicates they should be served. All I can say is, if I had a choice of having a steady diet of them in order to survive or starving to death, starving would be a serious consideration. However, there are people that swear they are Gods' gift to mankind. To each his own. Bug