Hotaru are small flying Badniks that appear in Sonic CD. Based on fireflies, these robots can light up dark areas with the large bulbs on their backs. They typically fly in swarms and are capable of working together to form a line of electricity between them in order to zap any enemies caught between them. Hotaru can also fire lasers from their tails. They appear in the Stardust Speedway and Metallic Madness stages.