I have a bit of familiarity with two violently and spontaneously reactive materials, elemental sulfur and aluminum alkyls. You don't want to mess with these except in very controlled conditions and containment. For example, a shipping container bobbing in the ocean is the opposite of a controlled condition. For these two materials, liquid water or humidity in the air = kaboom.
I am curious about what hazard occurs when sulfur is exposed to water. I used to buy jars of sulfur at the drugstore when I was a kid (for gunpowder and stink bombs, if you must know) and don’t remember any cautions about getting it wet. Even the SDS for sulfur doesn’t mention reactivity with water.