Skandapurana 1.4.7.58

1.4.7.58

evaṃ tadā damanakotsava īśvarasya āṃdolanena nṛpaveśmani me'vatāraḥ..
śambhorgaṇatvamabhavacca tathāgniveśyaśāpena gṛdhra iha bhadra tavedamuktam.. 9.58 ..

Thus, at that time, during the damanaka festival of Īśvara, my descent took place in the royal palace through swinging, / and my status as Śambhu's attendant came to be; likewise, by the curse of Agniveśya, I became a vulture here, O noble one. This has been recounted to you.