An object larger than Jupiter doesn't change its course because of chance encounters with other random small bodies.
> Could be a strange object with capability to disrupt the sun somehow?
This doesn't make physical sense.
> Why would an object hitherto unbeknownst to us and close to the sun NOT be scary?
Because it's had no observable effect on us for the last 4.5 billion years of our solar system's existence, and we've postulated nothing that would change this stable dynamical relationship?