To complete the 'What Goes Around' quest in Arc Raiders, players must destroy any ARC enemy using a Fireball Burner, which is a rare reward offering a full outfit.
The Fireball Burner can be found by defeating the Fireball ARC in specific locations: Water Treatment, Research & Administration, and Control Tower buildings in Dam Battlegrounds.
Identify the Fireball ARC by its appearance: a ball with a blue scanner in front of it.
Defeat the Fireball ARC to obtain the Fireball Burner.
Author's summary: Complete 'What Goes Around' quest with Fireball Burner.