A group of Japanese teenagers are in a restaurant and complain about an offending smell that manifests just as a pale figure appears in the background. Later, on the subway tracks, they smell the offending odor again and see the strange woman across the tracks who kills herself by jumping in front of the train, then staring down one of the men who has to crouch because of the overpowering smell. This video is actually a segment from a 2008 Japanese found footage horror anthology movie called Ura Horror. This isn't the only segment that's broken out from the show and blown up on creepy YouTube; after the mini-ghost-story, watch the exploding sea creature and the capture of a human soul escaping the body.
This video, uploaded by British water company United Utilities in April 2011, showed three clips of a maintenance robot running across some sort of creature in the sewers under the St. James neighborhood of London. The internet population quickly began wondering if this was some sort of genetic experiment or just an escaped monkey before someone put together that it was April and United Utilities had a “What Not To Flush” campaign running to educate people about proper sewer usage. Yeah, a water company pulled a viral April Fools' Joke that’s still circulated as legitimate. It only lives on because of how creepy it it.
A headless goddamned ghost appears right in goddamned front of them. You literally see it materialize on camera -- of all the entries on this list, this is the one you absolutely have to watch (here's a shorter version that cuts right to the ghost if you don't have 4 free minutes). Seriously, your mind will be blown like Eric Stoltz's penis in The Rules of Attraction. As they swing the camera lazily through the room, the ghost just walks very purposefully toward them like it's delivering a pizza, while a long, low moan emanates from its phantom lungs.