Hell Ant was a female Cardian who appeared in episode 050. The aliens Ail and An were visiting the recently opened Virtual Reality Theater in the Juuban Shopping District. The arcade was extremely popular and there were very long lines to enter. Usagi, Ami, Makoto, Minako, Rei, Mamoru, Kenji Tsukino, and Shingo Tsukino were also visiting on the same day. Due to the immense popularity of the theater, the aliens believed that it would be an excellent place to steal human energy for the Makaiju. To accomplish this goal, they released the Cardian Hell Ant. She began work quickly, attacking several humans and draining them of their energy. The humans were quite confused; they thought that the Cardian was yet another fake monster. They tried shooting it with their laser guns, but to no avail. Kenji and Shingo witnessed the Cardian's attacks.
Shingo quickly ran to tell his sister that something was wrong. When he found her, she was with Mamoru. Mamoru left to help, and Shingo went with him to show him the way. Usagi was let all alone, so she transformed into Sailor Moon. Meanwhile, the Cardian visciously attacked Kenji. Ail told him to "relax and rest a while," because he was not interested in killing him. Like the other humans, Kenji attempted to shoot at Hell Ant with his laser gun, but it had no effect. Hell Ant grabbed his laser gun, which was attached to his back pack, making him unable to escape. Eventually, the wire connecting the gun to his backpack broke and he fell to the ground. Luckily, Mamoru and Shingo arrived just in time. Mamoru threw his chest guard at the monster to distract her, but she attacked the two of them. Mamoru grabbed Shingo and they leapt out of the way. Kenji threw a fire extinguisher from behind the monster to distract her again, yelling, "It's a parent's duty to protect his beloved child!" before spraying her with the fire extinguisher. Unfortunately, his method did not work, and Hell Ant was able to grab Kenji, Mamoru, and Shingo to drain their energy. Mamoru was the only one left conscious, so An told Hell Ant to go easy on him (she had a crush on him).
Sailor Moon soon arrived on the scene to confront the villains. At An's instruction, Hell Ant moved to attack. Sailor Moon began her "Moon Tiara Action" attack... but it didn't work! Her tiara stopped mid-air and fell to the ground. Needless to say, she was extremely confused by this! Mamoru, whose memories had not yet been restored, did not recognize his former ally. Hell Ant swung her tentacles at Mamoru and Sailor Moon, causing them to stumble and fall. Suddenly, a white rose flew through the air and the Moonlight Knight appeared. Hell Ant screamed and rushed forward. Moonlight Knight brandished his scimitar and attacked, cutting off the Cardian's tentacles. Thinking that he had incapacitated her, he sheathed his sword. However, even more tentacles sprung forward and grab him. Fortunately, the other Sailor Senshi soon arrived on the scene. Sailor Mercury used her Sabão Spray attack to obscure Hell Ant's vision, while Sailor Mars used Fire Soul to sever the tentacles that ware binding Moonlight Knight. Sailor Moon told her friends that her tiara was no longer working. They were shocked! Sailor Venus picked up that her tiara was no longer working. They were shocked! Sailor Venus picked up the tiara and gently told Moon to pull herself together. Sailor Venus and Sailor Jupiter quickly used a combined Crescent Beam/Supreme Thunder attack to destroy Hell Ant.
(Source: The Oracle :: BSSM Encyclopaedia)