Mathematically, it’s possible, but scientists are still skeptical about whether or not they are real. They’re called white holes and you can actually create a model of one in your kitchen sink. If you let the water just hit the bottom and spread out evenly in all directions, you can kind of visualize the way it’s supposed to work. Action Lab on YouTube actually has a pretty good video about it which I suggest watching if you’re interested. youtu.be/p3P4iKb24Ng?si=b3_RHuj0J3F_7DC1