At http://spaceweather.com (August 31st, 2017) we have this image …
…. which appears to be a new kind of sprite caught on camera. Until fairly recently upper atmosphere lightning was deemed an impossibility by mainstream. Scientists now recognise space lightning in the form of sprites, elves, gigantic jets, and gnomes. It sounds like somebody in astronomy has swallowed the works of Tolkein but I suppose they have to get new names for new phenomena from somewhere, even if it's all just a case of lightning. It is also known as Transient Luminous Events (TLEs) which is more apt – but even that can be confusing as we are talking about lightning.
Sprites seem to sprout from above thunder clouds and reach up towards space (or the top of the ionosphere). The image above was seen over Oklahoma and a curve of lightning can be seen behind the main cluster. It may a form of gigantic jet rich in positive charge forced to bend around the cloud of positive charge produced by the sprites.