Fireflies are insects from Black & White. They are represented by bright blue balls of light that can be seen during nighttime.
Fireflies hide beneath objects like rocks and trees when the morning comes. If the object they chose to hide under is picked up, a random One-Shot Miracle will be revealed.
Fireflies can be a powerful resource, if one has the mind and patience to use them. Whenever you see fireflies flitting about your village, always try and plant several bushes and trees nearby; you never know when you might get something really useful, and more miracles is always a good thing.