I saw black sphere about a meter in diameter and it was sliding infront of our first floor living room window on NYE 2021 10.10pm on Clearance Road, Wimbledon , UK. It had no lights and made no noise. It moved as if organic almost. As if our phisics did not apply to it- not affected by wind or anything in its movement pattern. Like the background was moving arround it rather than it itself sliding in a straight line (something to do with gravity or magnetism it seems). It moved fluidly as if shapeshifting- nanobots or mercury perhaps, who knows. It was all black (visible against the grey clouds that night) and the only reason I saw it was that my cat ran away terrified from it (first his neck extended in order to see it, then he ran off with a big tail but very low to the floor). I didn't film it as though it was a bag or a baloon at first and fully intended to grab it if possible, let the kitty sniff it so he knows it's not dangerous and bin it...that is until it made a 90 degree turn towards me and stopped outside my window just out of reach. We just then stared at eachother for 20-30 seconds about a meter apart. As I started to open the window to try and grab it (as stupid as that in retrospect was)... it shot up with extreme speed without any acceleration time above the house. That's the point it finally fully dawned on me this was something incredibly strange. I've done quite a bit of research since and the same object was seen in the same area a few hundred feet down the road above the hospital in Tooting , London in 2009 (https://www.surreycomet.co.uk/news/15828580.12-years-ufo-sightings-south-london-north-kent-north-surrey/). Aside from the Nasa official video from Mosul there are tons of videos now on TikTok with these spheres (some clearly fake but the one from Yorkshire this Feb 2023 looks exactly like what I saw:https://www.examinerlive.co.uk/news/local-news/strange-black-ball-ufo-caught-26239423 ). I don't believe this to be a new phenomenon. So not hostile in any imminent sort of way. No obvious advances in their design also indicates that these are just potentially stuck here and unlikely under ongoing development by some Earthly corporation or military. A new alien race showing interest in us? Maybe. They could be animals/civilisations that have always lived on Earth, machines that seeded Earth with life/ nanny bots keeping treats away from the silly apes, defence drones/probes, visitors from another planet/time/dimension. They could be predators, scientist or even refugees. It could be Zog from planet Zog or Dave from Texas behind these who knows... I secretly hope it could just be Amazon's new delivery drones. The fact these display no lights signals either biological nature or some sinister intent. Most reported UFOs displaying lights has always given me some comfort knowing they clearly must comply with some rules at the very least (like some intergalactic traffic code- if no lights you go to space jail). The scary thing about these black/ metallic orbs is...your friends rarely hide with lights off.