I would request you to shed some light on the bold red part of the following sentence. Is it OK? If so, could you please explain to me the nature of the sentence and give a few examples exactly of the same structure? As far as my humble opinion is concerned, I find something missing between ghosts and come, e.g, that had or who had.
1- The large ballroom was crowded with familiar [color=red]ghosts come to help celebrate her birthday.