Answer:
Ghosts visit Brutus on the eve of battle to hunt Brutus. He says that killing Ceasar nothing is changed in Rome, as another Caesar is leading the Roman empire.
Step-by-step explanation:
Also, the ghost is putting a worm of doubt into Brutus's mind, as he is going to the battle, the dead Ceasar is appearing to hunt him.
Brutus is between consciousness and sleep, but his fears are presented in a form of this monstrous creature that comes to his dreams to make him suffer.