Who attacks Jem and Scout? What happens to the assailant?

In the novel "To Kill a Mockingbird" by Harper Lee, Jem and Scout are attacked by Bob Ewell. Bob Ewell is the father of Mayella Ewell, who accuses Tom Robinson, a black man, of assaulting her. Bob Ewell, seeking revenge for his daughter's accusations, attacks Jem and Scout on their way home from a Halloween pageant.

During the attack, Bob Ewell attempts to murder both Jem and Scout. However, they are saved by Boo Radley, a reclusive neighbor who has been watching over them. Boo Radley intervenes and fights off Bob Ewell, ultimately fatally stabbing him with a kitchen knife. Boo carries the severely injured Jem home, and the incident leads to a resolution in the novel, concluding the story's major conflict.