Oooh wow! That might be the explanation for some instances that I've observed from myself, I sometimes emit a super quick flicker of light coming out from the tip of my fingers or toes when I hit something - like anything in the dark.
That's a fascinating fact! Humans do emit a small amount of light, known as bioluminescence, though it's extremely faint and falls below the threshold of human vision. This phenomenon is still a subject of scientific study and adds to the many intriguing aspects of our biological makeup.