Hotarion (ホタリオン,Hotarion?) is the super fast firefly Mechaniloid in Spark Mandrill's stage in Mega Man X. When entering the darkened areas of the stage, this robot will fly across, oftentimes too fast to dodge. But it lights up the path it flies through, making it both help and harm. In Mega Man Maverick Hunter X, this enemy reappears right before X fights Spark Mandrill for the last time.
A different Hotarion firefly appears in Mega Man X5 in Izzy Glow's stage and the last stage. It has two varieties of attack: one will materialize and fly in the direction of the player, and other will float high while making a wall of lasers. It's also the firefly that appears with the F-Laser.
Hotarion comes from hotaru, which means firefly in Japanese.