I apologize for lashing out. One of my players threw themselves in acid after they were fully aware it was in fact acid. I did not and still do not know how to deal with that.
In the very first D&D game that I ever played, our party was standing right outside the entrance to a dungeon. Part of the area was covered in a red energy field. Inside the red energy field, all of the grass was dead, and right on the border between the area inside the energy field and outside of it, there was a collection of dead animals, insects, and other forest creatures. As we watched, a little bunny came hopping up, hopped into the red energy field, and, the moment that it entered the field, instantly dropped dead.
Guess what one of our players decided to do next. Take a wild fuckin guess.
In our first dnd game, two of our characters had an argument. One picked up and threw our cleric into a puddle. Our DM told her to make a saving throw against drowning. She rolled 1 and started drowning.