In contrast to other natural phenomena, the true nature of ball lightning is still unknown. According to the most common theory, it’s an atmospheric electrical phenomenon, a type of lightning that resembles a ball, that occurs during a thunderstorm and moves in strange trajectories.

Some scientists think that ball lightning appears because of phosphenes (a phenomenon characterized by the experience of seeing light without light actually entering the eye) or simply hallucinations. Nevertheless, we can’t ignore witnesses who have faced this rare phenomenon, taken a picture or recorded a video — after seeing this, we know it can’t just be a hallucination.