Interesting terms: zombie and cockroach (as related to ideas).
"Zombie ideas are claims that should have been killed by evidence, but just keep shambling along, like the notion that vast numbers of Canadians, frustrated by socialized medicine, come to America in search of treatment. (It was in a paper about that and other myths that I first encountered the zombie terminology.) Cockroaches are claims that disappear for a while when proved ludicrously wrong, but just keep on coming back."
David C's Blog 