A bird.

Indra’s brother Twashta did not agree with many of his actions. To teach him virtues, he created a son called Vishwarupa. Vishwarupa had three faces and was also called Trishiras. He used one face to recite the vedas, the second for drinking soma and the third to watch the world. He started to meditate and though Indra was scared and sent apsaras to distract him, it didn’t work. In the end, Indra mounted the Airavata, went to the forests and killed him with the vajra. He was so angry that he got a carpenter named Thakshaka to chop off all three faces of Trishiras. From the veda spouting face flew out Kapinjara birds, from the soma drinking face Kalapinga birds and from the third face flew Tithiri birds as per Mahabharata Udyogaparva Chapter 9.