I was boiling water in a pot on the stove, waiting for it to bubble before adding the pasta. It had salt and a dollop of oil in it already. I checked the pot because it seemed to take longer than it should. I saw that a huge single bubble had formed in the pot, it was about to break the surface, where the oil was floating. I moved away quickly enough before the bubble broke the surface, the water shot out of the pot. What was that? I want to avoid this happening again. Maybe this has some significance, the pot was bigger than the stove plate and the big single bubble was near the side wall of the pot, where the pot was not touching the solid plate.