It has to be an actual food item, so elementary school paste and pencil erasers don't count. I'm a big food-geek, so I've had lots of weird stuff. Recently, I had fermented squid innards at a Japanese restaurant and that was pretty "challenging." One thing I couldn't eat was some lion jerky that a co-worker gave me (but I did try jerky made from camel, bear, elan and zebra). I gave a piece of lion to my cat and then chanted "Cannibal! Cannibal!" I actually find the slaughter of top-of-the-food-chain animals such as lions to be reprehensible, so please don't go all PETA on me. I normally wouldn't have eaten bear, either, but I justified it as payback for a bad encounter with a bear in the Sierras some years prior.