You've heard of black holes: those rips in spacetime that suck up matter into oblivion. Now scientists are proposing that we've seen evidence for the opposite of black holes, or white holes, which spew out matter into our universe instead.
Our universe is a weird weird place, and black holes are some of the weirdest things around. But mathematically, a black hole should be able to be reversed, making something that spews matter out instead of swallowing it. These "white holes" would operate differently than black holes do; they'd spontaneously pop into existence for an infinitely small amount of time and
barf out a bunch of crap expel a large amount of matter before collapsing in on themselves to form black holes, never to be seen again.
This sort of behavior is understandably tricky to observe, but scientists think that they may actually have spotted one. Back in 2005, a gamma ray burst was measured that didn't come along with the supernova that's typically associated with gamma ray bursts, and it's possible that the burst was instead caused by the collapse of a white hole.
What's especially interesting about white holes is that their spontaneous creation of matter is analogous to the Big Bang, to the point where they're also being referred to as "Small Bangs." They wouldn't have any fixed spacetime coordinates and wouldn't be detectable at all, but they could instantly appear literally anywhere, anytime and do their thing before collapsing again. There could even be one behind you right now.
So far this is all just conjecture, but the same was true about black holes up until just the last few decades. And as physicist Murray Gell-Mann famously said, "everything not forbidden is compulsory," so at least from a quantum mechanical perspective, white holes must definitely be out there.