When I was about 10 or 11, we all went to Yellowstone.
A week after we were there, there was a report of a young boy (don't remember the age) who ran and went into one of the hot mud pots.
They had to retrieve what remains they could, just bones, using a special wire "scoop".
They said he probably only had a second or two of feeling anything, before his entire body shut down and started dissolving.
Within the last year or so (that I can remember) some guy either stuck his hand or foot in one of the pools.
Needless to say, he suffered a great deal of damage.