Akumuda was a Droid belonging to Petz and Calaveras which appeared in episode 69.

In that episode, Rubeus sent Petz and Calaveras to hunt down Chibiusa after she accidentally released one of her moonbeams. As the two sisters chased the girl through a park, Sailor Moon arrived to stop them. Calaveras summoned Akumuda to deal with the Sailor Senshi, and the droid promptly put Sailor Moon to sleep.

When the other four Senshi arrived, Petz and Calaveras departed, but left orders for Akumuda to deal with them as it had already done with their leader. When Akumuda attempted to put them to sleep as well, Sailor Mars fought back with Akuryo Taisan, causing the droid to retreat; it turned into a cloud and disappeared into Sailor Moon, who was still trapped in an eternal nightmare.

After Tuxedo Mask finally awoke Sailor Moon from the nightmare, Akumuda reappeared and pulled a sword from its forehead, then used that to attack. It managed to wound Tuxedo Mask, but Sailor Moon destroyed it with Moon Princess Halation.

(Source: Project WikiMoon)