"King Sal Visits Kala Yavana", Folio from a Harivamsa (Legend of Hari (Krishna))
Kalayavan or Kālayāvan (Sanskrit: कालयावन) (Lit. 'Black Yavana,' Yavana meaning a Greek) was an asura who invaded Mathura with an army of thirty million yavanas against Krishna.
Kalayavana Surrounds Mathura Page from a Dispersed Bhagavata Purana Series - Brooklyn Museum
After the invasion, Krishna departed to build a city of Dwārkā amidst sea, transported all his people and left them there.
Krishna lured Kalayavan into the cave of the mighty Muchukunda, who upon being disturbed from sleep by his kick, cast a fiery glance and reduced him to ashes.
This legend appears to indicate an invasion from the Himalayas. According to the Vishnu Purana and Harivamsa, Kalayavan was the son of a Brahmin named Ganga, and a Yavana princess.