Acid Flies are harmless Rahi.
Acid Flies make their first appearance in BIONICLE Heroes. They are small blue winged Rahi. The are harmless, but give LEGO pieces. While some, such as Balta, cherish them, others, like the Piraka and Nuparu consider them nuisances.
Acid Flies appear commonly. Despite their menacing name, they do nothing to harm the Toa, and in fact, do nothing except for fly around. They give a small amount of LEGO pieces when destroyed, and usually emerge from destroyed flowers or equipment.