Sony is either preparing a few unannounced IPs for the public eye, or it's really concerned about the weather at Gamescom next week. Sony has trademarked "Rain" and "Until Dawn" in the US and Europe, both as "computer game software." The above image was included with the Rain filing via OHIM, the European trademark system.
Until Dawn was registered on OHIM in May and on USPTO in August; Rain hit both OHIM and USPTO on July 30. No additional information is provided in the filings, but OnlySP links the Rain trademark with a gif depicting an unknown PlayStation quick-time-event (mostly because it happens to be raining in the scene). The image in Rain's filing takes a more Limbo approach than the gif suggests, but for now any speculation is just that.
Sony's Gamescom press conference is on Tuesday, August 14, and the trademark timing seems right for a reveal.