As per Sthala Purana of Chidambara Nataraja Swami Temple, Adi Sesha manifested into saintly Patanjali to see Aananda tandava of Lord Shiva.
Adhisesha, the serpent who serves as a bed for the Lord in his
manifestation as Vishnu, hears about the Änanda thaandava and yearns
to see and enjoy it. The Lord blesses him, beckons him to assume the
saintly form of 'Patanjali' and sends him to the Thillai forest,
informing him that he will display the dance in due course.Patanjali
who meditated in the Himalayas during krita age joins another saint,
Vyagrapathar / Pulikaalmuni (Vyagra / Puli meaning "Tiger" and patha /
kaal meaning "feet" – referring to the story of how he sought and got
the feet and eyesight of a tiger to help climb trees well before dawn
to pick flowers for the Lord before the bees visit them).
The story of
sage Patanjali as well as his great student sage Upamanyu is narrated
in both Vishnu Puranam as well as Siva Puranam. They move into the
Thillai forest and worship Lord Shiva in the form of Shivalinga, a
deity worshipped today as Thirumoolataneswarar (Thiru - sri,
Moolatanam - primordial or in the nature of a foundation, Eswarar- the
Lord). Legends say that Lord Shiva displayed his dance of bliss (the
Aananda Thaandavam) - as Nataraja to these two saints on the day of
the poosam star in the Tamil month of Thai (Jan – Feb).
Book Preceptors of Advaita, which has collection of articles collected by Kanchi Kamakoti peetam, says Patanjali came to Gaudapada as Chandra Sharma aka Govinda Bhagavadpada. This book was published on diamond jubilee of Sri Chandraseksharendra Saraswati's ascension to the Pitha.
Govinda Bhagavadpada section says:
According to the Patañjali-vijaya, a work by Rāmabhadra Dīkṣita
written about 200 years ago, Chandra Śarmā is none other than
Patañjali himself. Feeling that Gauḍapāda was not likely to secure a
suitable disciple and thus might have to languish under his curse,
Patañjali took pity on him and was himself born as Chandra Śarmā. This
was but one more of the many roles that Patañjali played. Patañjali is
none other than Ādiśeśha. Among the roles he played, those of Lakṣmaṇa
and Balarāma may be remembered.
So, this makes Govinda Bhagavadpada same as Adi Sesha.