Also enjoyed in the past: frozen chicken feet. It really is so funny to me (and sort of terrifying to my boyfriend) to find one of those thawing in the bed or next to your magic mouse.
I love feeding my pets gnarly animal parts -- we have not even discussed tendons, tracheas, or hooves yet, but we'll get there. I was vegetarian for 16 years until approximately one year ago. Because I now eat the animals' meat, I appreciate that my pets will eat their bones, feet, snouts, ears, tendons, organs, etc. -- all parts that might otherwise go to waste. And really, if I was truly grossed out by animal parts, I shouldn't be eating animals.
$14.99 for hours of chewing fun for dogs and cats, creeping out your friends, and, most importantly, "using the whole buffalo."