This is exactly why we send astronauts to risk their life to service Hubble: in a paper published last week in the Astrophysical Journal, scientists detail the discovery of a new unidentified object in the middle of nowhere. I don't know about you, but when a research paper conclusion says "We suggest that the transient may be one of a new class" I get a chill of oooh-aaahness down my spine. Especially when after a hundred days of observation, it disappeared from the sky with no explanation. Get your tinfoil hats out, because it gets even weirder.
The object also appeared out of nowhere. It just wasn't there before. In fact, they don't even know where it is exactly located because it didn't behave like anything they know. Apparently, it can't be closer than 130 light-years but it can be as far as 11 billion light-years away. It's not in any known galaxy either. And they have ruled out a supernova too. It's something that they have never encountered before. In other words: they don't have a single clue about where or what the heck this thing is.