Make no mistake about it, either Nemesis or Planet X or one of the smaller rogues would wreak havoc with our world and create devastation not seen since ancient Biblical times and further back to the destruction of Atlantis. Nemesis would most resemble the fiery "ball of redemption" associated with the Catholic prophecy of the Chastisement while Planet X would not be easily seen, a dark planet, but its catastrophic gravitational pull would certainly be felt worldwide. At its closest it would resemble a second moon, but not bright, and without craters, more a dark blue, crimson, or purple, whatever its true color is. As to other rogues, they might resemble our moon or else would resemble Planet X, but be of different size (likely smaller).
Nemesis is particularly frightening as there is no known periodicity calculated for it, let alone a possible location determined for it in our solar system, since the assumption is that it left our system long ago and is many light years away.
Is either Nemesis or Planet X the prophesied Wormwood of Revelation?
Actually I doubt it very much. The action of Wormwood on the Earth is exclusively on its ENVIRONMENT and not some sort of destructive gravitational pull. It especially poisons our water supply, our rivers, streams, lakes, seas. That is the effect of RADIATION ... what would happen if a supernova exploded too close to earth. Astronomers say Betelgeuse is too far away to cause any damage to earth via cosmic rays. Of course they could be wrong, and if they are, we or our descendants will find out. It is more likely that a star much closer to earth that we do not know or suspect is close to becoming a supernova, suddenly explodes. That star would become Wormwood.
Is Planet X to be found in Revelation at all?
As I mentioned, we might not even be able to see it but it may get close enough anyway to cause great destruction. Or the Bible may have omitted its description ... but certainly not its effects:
And I beheld when he had opened the sixth seal, and, lo, there was a great earthquake; and the sun became black as sackcloth of hair, and the moon became as blood; and the stars of heaven fell unto the earth, even as a fig tree casteth her untimely figs, when she is shaken of a mighty wind. And the heaven departed as a scroll when it is rolled together; and every mountain and island were moved out of their places. And the kings of the earth, and the great men, and the rich men, and the chief captains, and the mighty men, and every bondman, and every free man, hid themselves in the dens and in the rocks of the mountains; and said to the mountains and rocks, Fall on us, and hide us from the face of him that sitteth on the throne, and from the wrath of the Lamb: For the great day of his wrath is come; and who shall be able to stand?
Revelation 6:12-17 pertain to the SIXTH SEAL and therefore MUST happen BEFORE the fire from the sky or an asteroid impact. It is a huge and destructive event felt worldwide ... and in keeping with a close call with Nemesis or Planet X. Either these pastor prophets are jumping the gun about fiery meteors and Apophis impacting earth in 2029 (2036 is more believable) or we have VERY LITTLE TIME before the dreadful opening of the sixth seal of Revelation.
But would every mountain and island on earth be moved out of its place? No, not by the action of Yellowstone alone. It would take something more ... something like Planet X.
But that is still a theory ... a total nuclear war would probably accomplish much of the same thing.