Acrobatic Sera-Sera - "アクロバティックサラサラ" - [Urban Legend] - Also often called "Akusera"(悪皿) for short)
• About this yokai: a mysterious being that resembles a tall, lanky woman dressed in all red with A wide-brimmed hat. (Notably, she does not wear any shoes.) She has 'silky, smooth hair' - [Hence the name: 'Sera-Sera' an onomatopoeia for 'Hair Swish.'] - Her left arm also appears to be injured as though it had been recently slashed multiple times. Her face has no eyes, just Black holes and a smile that cuts from ear to ear.
Akuserasera can be traced back to message boards (such as 2chan) starting in late 2008 & onwards - The name sounds silly, but the common 'origin story' is that Akusera is a ‘the ghost of a victim of suicide, that threw herself from atop a roof somewhere in Fukushima prefecture sometime around 2003.' [Further specifics on this case are unknown.] --Given the time frame of the posts & similarity in her appearance (and because she's yet another 'supernatural stalker') More often, she's theorized to be an alternate telling, derivative of, or even a continuation of the "Hachishakusama" story [Which was also posted sometime in late 2008.] or perhaps yet another derivative of "Kuchisakeonna." [Given the red dress and slit mouth appearance.] Though Many theorize that they're one and the same, Akusera is just as often considered a unique entity.
Over time, people added their own "true encounters" with similar ghostly jumpers & similar stories from across Japan and it sort of became a yokai associated with falling victims, ghostly jumpers, and the "healthy fear of heights in urban areas" if you've ever been walking around downtown and got dizzy looking up, or gazed at a city from a distance, saw someone behaving recklessly on a building top, or had an intrusive thought about these sort of things, perhaps you've also witnessed someone who wasn't even really there...
• See also: Kuchesake Onna, Hachishakusama, TurboGranny.
• Personal Note: it's most definitely unrelated, however... she reminds greatly me of the "Lady in Red" (a well-known ghost from my hometown of Vancouver BC.) who has occasionally been seen dancing on the 14th floor of the Fairmount Hotel, She's very often said to have be a car accident victim.