Watching a cooking show where one chef prepared a molecular gastronomy dish. I was just thinking, these shows love to throw chefs for a loop with bizarre ingredients like Fruit Loops. Then I started to think: what edible things are unimaginable in a dish?
I have three:
[ol]
[li]Toothpaste[/li][li]Bubble gum[/li][li]Mouthwash[/li][/ol]
Any others?
Mouthwash, as I understand it, contains ingredients to make one ill if it is swallowed in any quantity, at least as formulated here in the US.
I’ve never seen a recipe calling for peanuts in the shell, though many people do eat them shell and all.
Also, most toothpastes (at least, that I’ve encountered) aren’t meant to be swallowed- small amounts have never hurt me, but they do put the poison control number on the tubes, and I suspect it’s not just to avert lawsuits.
Well, I wasn’t thinking of a toothpaste sarnie per se. 
More of, “instead of a raspberry coulis, I used Aim.”
Egg shells can probably be eaten fairly safely if broken up finely enough (true for most solids isn’t it?), though I don’t know why anyone would WANT to.
How about the vein from a shrimp/prawn? The poop chute thing. It’s edible (I often don’t remove it when I’m eating them, I know, ewwww), but would a recipe ever call for them SPECIFICALLY to be added to a dish?
I’ve had Bubble-Gum Ice Cream as a kid, so there’s gotta be a recipe for home-made ice cream where bubble gum comes in to use.
How about eyeballs? Are they ever called for in recipes? I know that sometimes people will eat the eyes of an animal that they roast whole… but are they ever added to anything else?
And then… what about… anus?
Aren’t anuses (ani?) used in haggis, hot dogs, and scrapple?
I can imagine sending my dish back at a restaurant because the anus wasn’t fresh enough (I think I just threw up in my mouth a little).
Based on watching Andrew Zimmern eat grilled skewers of chicken tails, uteri, and combs, among other bits, I have no doubt that somebody is selling charcoal grilled assholes somewhere in Tokyo.
The Mexicans do an eyeball taco.
Kittens.
One thing I learned from the old TV show Fear Factor is that there are thousands of species of beetles, and every single one of them is edible.
(The contest was called “Bowling for Beetles”. Each contestant bowled one frame and the number of pins left standing was how many live beetles they had to eat. I don’t know if they psyched themselves out or what but all of the contestants did poorly)
There are plenty of Chinese recipes that feature cat. The Swiss, Italians and Basques have also historically eaten cat.
Bodily fluids of the sort commonly involved in oral sex.
I said kittens.
You’re kidding, right? There’s a recipe right here on the SDMB for that.
The first time my youngest son was offered a boiled egg in the shell he ate it shell and all. He said afterwards he just didn’t realise he wasn’t supposed to. His older brother had eaten eggs out of the shell in front of his younger brother often enough that it just never occurred to us that the younger wouldn’t have seen how it was supposed to be done. No harm done. And at least he got some calcium.
Roast toddler.
i remember a comedian saying " order weird things to be difficult…like candied goat anus
Toenails, fingernails and hair.
Meg Griffin made hair pie once. Earned Brian a punch in the mouth. I guess that could be a side dish.