There is much controversy around Orbs which usually appear in photographs and can also appear and disappear from a photograph. Some people can actually see them.
Ghostudy.com says “Orbs have many names including globes, globules, balls of light, and hovering round balls. They appear in all ranges of brightness from bright & glowing to faded & barely visible. They are usually quite fast and follow an erratic pattern of flight. Positive orbs are believed to be the spirits of the dead by many. However, other theories suggest that they might be separate life forms or even nature spirits. The problem is that many orb photos are false positives.”