Originally meant to be aired on April Fool's day, this hoax documentary's broadcast had be moved to a different date, and, as a consequence, many naive viewers thought it was real. Now, the hoax has taken a life of its own on the Web, with waves of naive people believing its silly made-up claims about scientists working in certain fields mysteriously disappearing. The hoax has even made the HN front page. Sigh.
Years later, I found out it was completely fake; the end credits even tell you it's fake (I missed that). I had a hard time believing anything after that realization.
* - Mermaids: The Body Found