Well, it may not be the mysterious Planet X that even NASA seems to credit with some degree of proof - albeit mathematical only at this stage (
https://solarsystem.nasa.gov/planets...et-x/in-depth/) but 2015 TG387 (nicknamed The Goblin) certainly ticks a couple of the boxes.
The Caltech researchers propose a planet with a mass of 10xEarths travelling in highly elliptical orbit well beyond Pluto's and about 20 times farther from the sun on average than Neptune. It may take between 10,000 and 20,000 Earth years to make one full orbit around the sun.
Well, The Goblin takes 40,000 years its highly elliptical orbit. And " at its most distant, ... is 2,300 times further from the sun than Earth but only 65 times at its closest. Pluto's orbit, by comparison, is approximately between 30 and 50 AU.
OK. It's also small - 300 km in diameter. And OK, perhaps it doesn't tick all that many Planet X boxes after all. But it does add another proof to the growing body of evidence for more extra-Pluto planetary bodies.
Note that I have not once mentioned Nibiru.
Peter