When Rama spared Ravana for being unarmed, Ravana returned from the battlefield humiliated. Instead of going back himself, he decided to send his brother Kumbhakarna to fight Rama and Laxmana.
Kumbhakarna, who used to sleep for six months at a time, became furious when he was awakened. Ravana explained the urgent situation to him and asked him to leave immediately.
Seeing the gigantic Kumbhakarna arrive, the monkeys started fleeing in all directions. Kumbhakarna then grabbed a handful of monkeys and ate them.
Meanwhile, the arrows that Rama and his army fired at Kumbhakarna broke on hitting his strong body.
Finding the arrows ineffective, Rama decided to cut off his head. So he flung his chakra and served the demon's head. The monkeys came back once again and rejoiced on seeing the dead body of the demon.