Mermaid is pulled from lake by men in biohazard suits, Poland. Sept 2015, Video, UFO Sighting News.

Date of discovery: Sept 2015
Location of discovery: Poland
News source: http://www.mirror.co.uk/news/weird-news/watch-bizarre-video-showing-merman-6523679

Yes this is kinda clear and not a UFO, but it does seem to show a mermaid that was found on land, probably dead. Its been long believed that there are many species of aliens that visit Earth, merpeople are one of them. Since the ocean covers 75% of the Earth, this planet is a paradise for them. 
Scott C. Waring

News states:
Creature that looks like Mermaid is pulled from lake by men in biohazard suits. "This incredible video appears to show the moment a MERMAN was pulled out from a lake, put on a stretcher and taken away by mysterious officials. Captured in Poland, the short film shows a group of men in what look like white biohazard suits working with others dressed in attire similar to paramedics. Lasting two minutes, the footage begins with the men in white suits surrounding a mysterious body on the banks of a river. The men then lift the shape up at which point, what appears to be a large fish tail is clearly visible. At this point the men dressed as paramedics then move a stretcher into place while their biohazard suit-wearing colleagues bring the 'being' up to them. As they place the unknown shape on the stretcher, the 'Merman' is clearly visible and lies down - his long beard resting on his chest. The men dressed as paramedics then wheel the 'Merman' away to an unknown location and no-one has heard anything of the incident since. After the footage was posted online, a number of people claimed it was proof of Mermen existing, while others said it was either a hoax of the filming of a movie ( via mirror.co.uk )."