Marine aquarium cautions

[Patrice]

A year ago, while I was cleaning a tank, there was some kind of "smoke" that came out of a rock when I moved it. I have no idea that was. Anyway, it was painfull.
It's hard for me to explain this in english. At first, it was just painfull but after 20 minutes, it was like my hand got scrubed on a hard surface. I immediately washed my hand but it did not stoped. The "scrubbing effect" of that smoke have last for about 20 minutes. I was a little worry let me tell you. That was weird and I would love to know what that was.