Inexplicable Lights
Here’s something you can try to do at home, assuming that you have strong speakers and don’t mind deafening your entire neighborhood. If you play a loud enough sound to pop underwater bubbles, they’ll produce a quick flash of light. The light isn’t blindingly bright, but it is shocking if you’re not prepared for it.
Why this occurs, nobody can answer. In the 1980s, scientists theorized that the light was created by friction, but more modern researchers found this not to be the case. The gas inside of the bubbles becomes superheated and glowing plasma that extinguishes as soon as it appears. Why plasma appears in the first place is the real mystery.