Collectors Weekly has a fascinating piece on a tour of H. Fishlove & Co's factory, where they make Whoops, the original fake vomit. And while experts know the ingredients, apparently the formula is as closely guarded as Obama's underpants.
Mardi Timm, co-owner of one of the largest novelty collection in the world, says nobody really knows how to do them:
It is a secret recipe. But I think we know what's in it. It's got foam pieces cut up, and it's got latex. But the actual recipe, nobody outside the company knows that.