The Moth was experimented on in the Umbrella laboratory underneath Raccoon City. The first version of the T-virus infected moth grew to a great size but its wings remained small, thus its mobility was limited. The Moths were able to secrete a powder that is highly poisonous. Just like normal moths, these moths lay eggs, however their larva was rather overgrown. Once the Raccoon City outbreak occurred the Moths took siege of the laboratory and turned the entire area into a makeshift nest. While not the most aggressive of foes, their poison made them a threat to Leon and Claire.

In Rockfort Island a different form of moth was created. This moth was far smaller but its wings were of the right proportion, so it was able to fly as conventional moths. It still had the same poisonous secretions but now with far more mobility. A major difference of this moth is that it lays its eggs on living organisms, the larvae would grow as parasites within the animal and feast on their most unfortunate host.