If the nucleus is actually as large as everyone is speculating, as large as jupiter or larger, what kind of gravitational influence would one suppose it has?

I have done a lot of research on planet x, or nibiru, or what have you, and one of the main points that I find repeatedly used by debunkers is that an object as large as a brown dwarf, or another Jupiter sized planet coming through the inner solar system would seriously disrupt the orbital patterns of the planets. If ISONs nucleus is really as large as Jupiter, and a solid mass, it would have to have insane gravitational influence.

What do you guys think?