"Monkeys are proud of their tails!" Ravana snarled. "So I will burn this monkey's tail. Let him feel both pain and shame!"
Musicians played while the rakshasas wrapped Hanuman's tail with oil-soaked cotton. "Now the torch!" barked Ravana, and Hanuman's tail burst into flames. Then Hanuman leaped up and set Ravana's throne-room on fire.
Then the whole palace.
Then he proceeded to burn all of Lanka, house by house.
But Hanuman did not burn the Ashoka Grove where Sita was praying to the fire-god Agni. "Please keep Hanuman safe, O Agni!" said Sita. "Do not let the fire harm him."