Thiruvilayadal

Lord Shiva gives a sacred fruit brought by sage Narada to his elder son, Ganesha for outsmarting his younger brother Muruga in a competition for winning the fruit. Angered by his father's decision, Muruga goes to the hill abode of Palani in the guise of a hermit. Goddess Parvathi comes and narrates four of the divine games of Shiva to calm Muruga down.The first story tells of the opening of Shiva's third eye when he visits Madurai, the capital city of the Pandya Kingdom, ruled at that time by Shenbagapandian. Shenbagapandian wants to find the answer to a question posed by his wife (whether the fragrance from a woman's hair is natural or caused by the cosmetics she uses on her hair) and announces a reward of 1000 gold coins to anyone who could come up with the answer. A poor poet named Dharumi desperately wants the reward and starts breaking down in the Meenakshi Amman Temple. Shiva, who hears his cries, takes the form of a poet and gives Dharumi a poem containing the answer. Overjoyed, Dharumi takes it to the court and recites the poem, but the ego-filled Tamil poet Nakkeerar claims the poem's meaning to be incorrect. After arguing with Nakkeerar about the poem's accuracy, Shiva burns him into ashes. Later, he revives Nakkeerar, saying that he only wanted to test his knowledge. Nakkeerar requests the king to give the reward to Dharumi.The second story is when Shiva marries Dhatchayini against the will of her father Dhatchan. Dhatchan also performs a Mahayagna without inviting his son-in-law. Dhatchayini asks Shiva's permission to go to the ceremony but Shiva refuses to let her go as he feels no good will come out of it. Dhatchayini disobeys him and goes there, only to be insulted by Dhatchan. Dhatchayini curses her father and returns to Shiva to find him angry at her for disobeying him. Dhatchayini asserts that they are one and without her, there is no Shiva. Shiva refuses to agree with her and burns her to ashes trying to prove her wrong and performs his Tandava, which is noticed by the Devas, who pacify Shiva. Shiva decides to restore Dhatchayini to life.The third story describes Parvathi being banished by Shiva when her attention wavers for a moment while listening to Shiva, who was explaining the essence of the Vedas to her. Parvathi, now born as Kayarkanni, is the daughter of a fisherman. When playing with her friends, a strange fisherman (Shiva) approaches and flirts with her, despite her disapproval. The fishermen often face problems due to a giant shark that disrupts their way of life. Shiva asserts that he alone can defeat the shark. After a long battle, Shiva kills the shark (which is actually Nandi) and remarries Parvathi.The last tale narrated by Parvathi is when Shiva takes the form of a firewood vendor. Hemanatha Bhagavathar, a skilled singer, tries to conquer the Pandya Kingdom when he challenges the kingdom's musicians. The King's minister advises him to seek the help of Banabathirar, a devotional singer, to challenge Hemanatha Bhagavathar. When all musicians reject the competition, the King orders Banabathirar to compete against Hemanatha Bhagavathar. Knowing that he cannot win, the troubled Banabathirar prays to Shiva. Shiva, in the form of a firewood vendor, shows up outside Hemanatha Bhagavathar's house and shatters his arrogance by singing the song, "Paattum Naane". When Hemanatha Bhagavathar comes to know that the vendor was Banabathirar's student, he gets embarrassed and leaves the kingdom that very night leaving a note to Banabathirar informing him of his departure. Shiva gives the letter to Banabathirar and reveals his true identity to him. Banabathirar thanks Shiva for his timely help.After listening to these stories, Muruga's rage finally subsides and he reconciles with his family.

Question: Why does Shiva Burn Nakkeerar to ashes in the first story?