The bully might face physical retaliation. For example, if a bully has been constantly picking on someone weaker in a schoolyard and one day goes too far with insults or pushing, the victim might fight back. This could lead to both of them getting in trouble with school authorities.
Socially, the bully could become isolated. When they push someone too far, the victim may speak out and expose the bully's actions. Friends and peers who were previously on the fence about the bully's behavior might turn against them. This can also lead to a loss of respect within the community or group. For instance, in a sports team, if a bully keeps harassing a teammate and finally goes too far, the whole team might ostracize the bully.