There is this star which they say it might be the partner of our sun if we consider it being a binary star system and they call it "nemesis" and saying every 70 million years it orbits our sun and the reason for last extinction event might be it passing near sun and disrupting asteroid belt causing a few of them to come our way.
Another one says solar system orbiting the galaxy actually goes above the disk and below it a movement like wave and when in those areas the electromagnetic shield of the milky way galaxy is at it's weakest state and we get bombarded by asteroids and lethal cosmic rays, but now we are I think nothing to be worried about.
There are more celestial bodies out there than anyone can ever imagine.
This is obviously a joke, such an object would be visible to the naked eye... and we'd have a VERY elliptic orbit.
Knowing that there's people that take this kind of jokes as facts obviously justify other people to me : the ones that believes that a bearded , bored guy, drown his creations(and ego bloating slaves) because they don do what he wants them to do.
I read about this in Discover magazine