A Terrible-Monster created by fusing a Space Monster with an ant. Aribunta was raised by Yapool’s servant, Guironian, to create an underground fortress below Tokyo. Aribunta created a four-dimensional ant colony to kidnap women with blood type O. It sucked on their blood to grow stronger. Aribunta spews a powerful acid from his mouth, and can release flamethrowers from the spikes on each hand.

Aribunta hid underground, feasting on the blood of women unlucky enough to fall into his ant colony. After Aribunta attacked an underground train, he destroyed TAC’s almighty Duckbill tank sent underground to investigate.

Later, Yuko Minami fell into the colony with Seiji Hokuto and they transformed into Ultraman Ace. Aribunta attacked Ace with its acid spray, but escaped above-ground after being hit with a Metalium Beam. Ace escaped from the colony and followed Aribunta above-ground where Aribunta and Guironian overpower him. However, Zoffy arrived to turn the tide of battle. In the end, Zoffy and Ace rammed Aribunta and Guironian together and killed them both.