Charioteer of Indra. Chapter 69 of वामन पुराण gives the following story about the birth of मातलि .

A child was born to sage शमीक . It was the time of देवासुर war. A great army of असुरस् under the leadership of अन्धक attacked देवलोक and conquered it. In the great battle with अन्धक the वज्रायुध of इन्द्र broke into two. इन्द्र was thinking of a new weapon for him. महाविष्णु then appeared before him and advised him to praise the glory of अग्नि . इन्द्र did so and then a divine weapon rose from the fire. इन्द्र flew at the असुरस् carrying the new weapon. There was no clever charioteer to drive the chariot of इन्द्र . Still, seated in the golden chariot given to him by the वसुस् इन्द्र drove very swiftly against the असुरस् . The earth shivered by the din of the chariotwheels.

When the earth began to quake the sage शमीक following directions of his wife तपस्विनी placed the child on the ground outside the hermitage. An astrologer had told her that a child would become two if it was placed in an open ground at the time of earth-quake. तपस्विनी wanted one more child. As soon as her child was placed on the ground another child identical in every respect with the first one was born by the side of the other. But the second child, as soon as it was born rose up and ran to इन्द्र for driving his chariot.

When the गन्धर्वस् knew he was coming to help इन्द्र , they showered him with brilliance and the child approaching इन्द्र said "Oh, Lord of the देवस् , I shall be your charioteer." इन्द्र asked him, "Child, whose son are you? How will you drive my horse? I doubt your competence." The child replied, "I am the son born to शमीक on the ground. I have been given power and brilliance by the गन्धर्वस् and so I am capable of driving your chariot." On hearing this, इन्द्र accepted him as his charioteer and named him मातलि .